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1 Table of Contents Acknowledgments...2 Executive Summary...4 Project Background...5 Existing Mechanical System...8 Proposed Mechanical Redesign...13 Impact of Proposed Mechanical System on Structure...36 Impact of Proposed Mechanical System on Electrical System...39 Design Summary...42 List of Figures...45 List of Tables...46 Works Cited...47 Appendices...48 Page 1

2 Acknowledgments I would like to take this opportunity to thank some of the people that have contributed to this final report, and to making both my present personal life as well as my future professional career as bright as they are now. Without the help and friendship of those mentioned below, I would not be the person that I am today. First and foremost I would like to thank my father Ralph, mother Susan, and sister Lynsey. As a family we have had to overcome several challenges throughout the last couple years. However, through our constant support of each other, we have met and overcome these challenges. It is because of this constant support from all of you that I have accomplished all that I have, and will continue to succeed in my future endeavors. I would like to thank my girlfriend Janet. Our relationship and the time I have spent with you have helped to keep me sane throughout the development of my thesis. I look forward to continuing to spend time with you, especially now that we have more time to spend. I would like to thank the faculty and staff of the Penn State Architectural Engineering Department. Throughout my academic career I have developed my technical skills to higher and higher levels because of the instruction and guidance provided by the faculty of the department. I would like to think in particular the members of the mechanical staff, my thesis advisor Dr. Srebric, Dr. Freihaut, and Dr. Bahnfleth. I would like to thank Professor Parfitt and Jonathan Dougherty for their management and advice throughout the thesis process. I would also like to thank my undergraduate adviser Dr. Horman. I would like to thank the professionals that made contributions to my thesis work throughout the past year. In particular I would like to thank Richard Naldrett for walking Page 2

3 me through the existing mechanical system, Frank Watkins for providing me with a full set of drawings, and John Vucci for discussing the existing conditions of the building with me. Last but not least I would like to thank the friends I have made throughout the years in the AE department. In particular I d like to thank Patrick Dempsey, Katie McGimpsey, Brad Cordek, and Selim Ercan. I hold very dear to me the friendships I have developed with you all and I know that they will continue to remain after we have left Penn State and continue on in our lives. Page 3

4 Executive Summary The following report is the product of a year long investigation of the mechanical system at the University of Maryland s Gossett Field House. During the fall semester, existing conditions for the building were documented and a series of technical summaries were produced, as well as a proposal for redesigning the mechanical system. The spring semester was used to carry out the proposed redesign and this report is the final summary of that process. Within this document you will find the project background outlined and a brief description of the existing mechanical system in place at the building. The report goes on to outline the redesign process, such as HAP load analysis and annual cost summaries that were generated for both the existing and the proposed mechanical systems. The design of the proposed system is also documented and explained. After the proposed mechanical system has been designed, the impact of this system was evaluated on both the structural and electrical systems. Page 4

5 1 Project Background 1.1 College Park, Maryland is located just north east of Washington DC, located off of the Interstate 495 Beltway. The university itself is a major public research university located on 1,250 acres of rolling land. The enrollment at the university consists of 35,000 Figure 1 Location of College Park, MD students, 25,000 undergraduate and 10,000 graduate students. There are 13 colleges within the university that offer 111 undergraduate majors. The total budget for the university is $1,132.5 million, $279.7 million of which comes directly from student tuition and fees. The university has 27 NCAA Division I athletic teams and 346 male student athletes. There are currently 115 athletes listed on the University of Maryland football roster and 17 coaches. Due to the recent success of the Maryland football program, in 2001 the university initiated a phased renovation and expansion of Gossett Field House, a facility for the UMD football team located at the north end of Byrd Stadium. Phase one of the project completed from consisted of the renovation of the 40,000 square foot existing facility. Phases two and three took place from and consisted of a 25,000 square foot expansion of the facility. The total cost of the project to the university was $10 million. Page 5

6 1.2 Building Overview Gossett Field House is a 65,000 square foot multiple occupancy type facility. The first floor is all renovated facility, consisting primarily of a weight room, locker rooms, showers, and mechanical/electrical space. The second floor has both renovated and added space. The renovated space consists primarily of office space and team meeting rooms. The additions to the facility include a full service buffet style kitchen and corresponding dining room with a terrace that looks over Byrd Stadium, a 350 seat auditorium, a class room section with a full computer lab and tutoring rooms, and additional office space, team meeting rooms, and a film room. The renovated sections make up 40,000 square feet, while the additions to the facility make up 25,000 square feet. Figures 2&3 Gossett Field House Page 6

7 1.3 Project Team Owner: University of Maryland General Contractor: Forrester Construction Architect: Bignell, Watkins, & Hasser MEP Engineer: Schlenger/Pitz & Associates Structural Engineer: Watkins Structural Group 1.4 Building Systems Electrical: A 3500A 480/277 service is supplied for the building. This main service is then distributed throughout the building using 5 transformers, some of which are 480/277 and some of which are step down transformers for 208/120. The distribution to the loads is then completed via 15 panel boards. Lighting: Lighting for the building is primarily provided by 2x4 and 2x2 parabolic troffers in conjunction with the appropriate fluorescent lamps. Additional lighting is provided by 6 recessed compact fluorescents as well as task and accent lighting consisting of 4 strip lighting. Structural: The foundation for this project consists of cast in place spread footings with a continuous footing foundation wall around the perimeter of the building. Above ground the construction consists of structural steel framing with open web steel joists and a concrete slab flooring system placed on top of metal decking. The interior walls are metal studs. The roofing system is a built up roof on metal deck supported by open web steel joists. Page 7

8 2 Existing Mechanical System 2.1 Design Objectives and Requirements The Gossett Field House project consists of a 25,000 sqft addition and a 40,000 sqft renovation of the existing facility for the University of Maryland football team. There are several unique characteristics of this facility that lent themselves to specific design objectives and requirements. The main objective undertaken by the design team during the planning of this facility was to provide the University of Maryland football team with a state of the art building dedicated solely to the football team. This facility was to include classroom space, a dedicated dining hall, and a state of the art auditorium. The university was hoping to sustain the success of its football program by banking on a new facility helping to draw recruits to the university as opposed to going out of state to other programs, thus ensuring their success for years to come. As with most universities with more prominent football programs, the football team brings in a large amount of revenue for the university, through ticket sales, sales of apparel, etc. This revenue was something the university was hoping to have for years to come as well, and was influential in their decision to renovate and expand the football team s facilities. That being said, one of the more important requirements for the project was to ensure that the existing facility would remain open to the football team during the times necessary. While the team now uses the facility year round, the university deemed it acceptable that the facility could be occupied only during the football season, and the bulk of construction being done in the off season. While this opened up more time for construction, it still placed limitations on the general contractor. For instance, the college football season is from September through November, and continuing on into December Page 8

9 and as late as the first week of January if a team makes a bowl game. In addition, there are summer practices for a month or more before the season starts. So while the general contractor had over half the year to perform most of the major renovation work without affecting the football team s use of the facility, this portion of the year consisted of the late fall, winter, and early spring months, which are not necessarily the best parts of the year to undertake major construction. Once the renovation work was done on the existing facility, it was much easier to work year round, without having any impact upon the football team s use of the facility. Aside from these unique and somewhat unusual conditions and requirements that were specific to this project, more common requirements also existed. For instance, the conflict between ceiling heights and mechanical ceiling space was a requirement created by the architectural design. The architect on the job wanted to keep the ceilings as high as possible, thus creating some design challenges, particularly in the new kitchen and dining room. In this particular space there is a large amount of mechanical equipment required such as the make up air units, exhaust fans for the kitchen hoods, as well as the supply ductwork for the heating and air conditioning of the space. Containing all of this ductwork within the ceiling why designing for maximum ceiling height was a large design challenge that required a creative solution. In addition to the limited ceiling space, there was also limited floor space for mechanical equipment as well. In the area that was to be renovated, no additional space was to be used for mechanical equipment. In the addition section of the construction the mechanical space was kept to a minimum. Because of this, the major mechanical equipment such as the packaged air conditioners and kitchen make up are units were located on the roof, while low profile variable air volume boxes were used as the terminal devices. Using the VAV boxes in this configuration allows for the maximum ceiling height to be maintained. The final challenge faced by the design team was the large amount of glass in certain parts of the facility. For instance in the new dining room addition, the walls Page 9

10 consisted entirely of glass. This posed a unique challenge of how condition the space, even with the high transmission properties of the glass. This problem was solved by using linear slot diffusers around the perimeter to create a buffer between the perimeter windows and the outside. 2.2 Design Conditions The following sets of outdoor and indoor design conditions were obtained from the design engineer and were used for all necessary calculations for the Gossett Field House Project. These conditions are as follows: Outdoor Design Conditions Summer Conditions Outdoor summer dry bulb: 94 F Outdoor summer wet bulb: 75 F Winter Conditions Outdoor winter dry bulb: 10 F Indoor Design Conditions Indoor Cooling Indoor dry bulb: 75 F Indoor Relative Humidity: 50% Indoor Heating Indoor dry bulb: 70 F Page 10

11 2.3 Air System Summary Gossett Field House has two distinctly different air systems to provide heating and cooling to the building. The first type of system services the existing part of the building that was renovated and consists of two air handling units, AC-1 & AC-2. These air handling units are located in the mechanical penthouse on the roof. Both of these units are variable air volume units with chilled water coils and steam pre-heat coils. Reheat is provided by duct mounted hot water booster coils. Terminal devices for these systems are ceiling diffusers. AC-1 has a ducted return and serves the existing office space located on the second floor. AC-2 is a 100% outdoor air unit with no energy recovery. This unit serves the first floor, which consist primarily of a weight room, player locker rooms for both the home and away teams. A schedule of the unit capacities is provided below: Table 1 Existing Air Handling Unit Schedule COOLING HEATING FAN (MBH) (MBH) CFM OA CFM ESP (IN. WC) AC AC In addition to the system mentioned above that serves the renovated section of the building, there is a completely different type of system that is used to serve the additions to the building. Six packaged rooftop units provide the heating and cooling to the addition sections of the building. These units are equipped with DX cooling and gas fired heating. RAC-1 serves the multipurpose room, RAC-2 serves the kitchen area, RAC-3 serves the team film rooms that were added, RAC-4 serves the new auditorium, RAC-5 serves the new classrooms and computer room, and RAC_6 serves the hallway that connects the auditorium and kitchen. RAC-1, RAC-2, and RAC-4 are constant volume units while RAC-3, RAC-5, and RAC-6 are variable air volume units. RAC-3 and RAC- Page 11

12 5 also use VAV boxes with hot water reheat as terminal devices. A schedule of the unit capacities is provided below: Table 2 Existing Packaged Unit Schedule FAN COOLING HEATING (MBH) (MBH) CFM OA CFM ESP (IN. WC) RAC RAC RAC RAC RAC RAC Hydronic System Summary There are several major pieces of mechanical equipment that provide the chilled water and hot water for the systems that serve the renovated section of the building. A single air cooled liquid chiller supplies the chilled water for AC-1 and AC-2. The chilled water is circulated by two base mounted pumps, one of which is on stand by. Hot water for the duct mounted booster coils and VAV reheat coils is provided via a steam to hot water shell and tube type heat exchanger. The hot water is then circulated to the coils via an inline circulation pump. Steam enters the building at 125 psi and passes through a pressure reducing valve resulting in 15 psi steam. Schedules for the existing mechanical equipment mentioned above are located in Appendix A. Page 12

13 3 Proposed Mechanical Redesign Objectives of the Redesign The purpose of this redesign is to improve upon the mechanical systems that are already in place. This does not reflect however, any poor design on the part of any of the professionals involved, because there may have been considerations that were taken into account that I am unaware of which influenced the design decisions. The system redesign is being undertaken for academic purposes, but there are several other objectives that I hope to accomplish. The first and most important in defending my redesign concept is to lower the life cycle cost of the mechanical system. First cost was a primary concern when the mechanical system that is in place was designed. However, an increase in the initial first cost of the facility could be justified by an equal or greater savings over the life of the installed system. One of the major components of a life cycle cost analysis is operation and maintenance costs. By installing a system that would reduce these costs, the overall cost of the system would decrease over the period of its service life. One of the contributing factors to the operating costs it the amount of energy required to run the equipment. If you reduce the amount of energy required, then the life cycle cost of the system decreases. By reducing the energy used, you are also having several other positive affects, including lower utility bills, lower emissions, and the conservation of energy sources. Another objective of the redesign will be to provide the occupants of the building with an equal or better indoor environment. Several factors influence the over all indoor Page 13

14 environmental quality. The controls of the systems play a large part. A series of controls that is properly sequenced to allow for any and all indoor and outdoor conditions possible provides for comfort for the building inhabitants at all times. Along with the controls is the ability of the system itself to properly heat and cool the building. Therefore it will be a priority to maintain or improve the level of comfort inside the building. This will be accomplished through the proper sizing of the new equipment for the proposed system Alternative Systems Considered When developing a viable alternative to system currently in place at Gossett Field House, several systems were considered and deemed inappropriate. These other considered alternatives are outlined briefly below. The first alternative considered was not a mechanical system itself, but a philosophy to be used throughout the building. The idea was to redesign the facility so that it met the qualifications for a Leadership in Energy and Environmental Design (LEED) certification. This concept was briefly examined in technical assignment #2 and it was indicated that the project lent itself to becoming a LEED certified facility. However, when examined in greater detail, it is easy to see why this avenue was not pursued during the original design. The facility is owned and operated by the University of Maryland, which while a large university, has to consider the initial costs of its facilities. So because each project has a limited budget, the increased benefit generated by obtaining a LEED certification would be heavily outweighed by the significant cost that would be added to the project. The second alternative was to use the concept of thermal storage. There is an ice storage facility located approximately 100 from the building. The facility is existing, so no real construction would have needed to take place other than to extend and connect the building to the existing facility if there was the required necessary capacity. However, upon further investigation it was found that the facility has no extra capacity. The University of Maryland has no central chilled water plant, so the ice storage facility was Page 14

15 designed specifically for the building load of a few adjacent buildings, with no consideration for further expansion given, and hence, no extra capacity. The third alternative considered is the closest to the system that I will use for my proposed redesign. While the University of Maryland does not have a central chilled water plant, it does however have a central steam plant. This alternative was to use both the central steam plant, in conjunction with a chiller plant to provide the heating and cooling necessary for the building. While this is a very good alternative, it is my belief that it can still be improved enough to warrant a similar yet slightly more energy efficient system. Several other alternatives were considered very briefly but then dismissed. A dedicated outdoor air system in conjunction with radiant panels was considered but written off as too impractical. An under the floor displacement ventilation system was also considered. However, the first floor sits on grade, so the amount of construction that would be required to raise the floor and give enough room to run ductwork is impractical Proposed Redesign The following redesign option is being proposed in hopes of both accomplishing the initial design objectives as well as the redesign objectives listed above in this paper. This semester has been dedicated to the research, design, implementation, and optimization of the following proposed system for the University of Maryland s Gossett Field House Scope As briefly mentioned in the previous section, I believed that using a central plant for the building would be a very viable solution. However, I believe this idea can be improved. In addition to a central plant I believe a series of rotary energy recovery wheels located in each of the air handlers would significantly reduce the building heating Page 15

16 and cooling loads. The ERVs to be used for the redesign will be both the sensible and latent type energy recovery wheels. Because the building is located in such a humid region, it is my belief that adding latent energy recovery would improve the effectiveness of the units. Whenever ERVs are used, cross contamination is always an issue. For the most part, the air being exhausted from the facility is relatively low contaminant air, with the primary exception being the kitchen area. It is my belief that the series of large exhaust hoods in the kitchen would provide a source of cross contamination. However, the wheels can be selected in such a way with the appropriate purge volume of air to eliminate cross contamination. Therefore, rotary energy recovery wheels will be used in all of the air handlers at Gossett Field House. The use of ERVs will significantly reduce the amount of heating and cooling required. I will try to optimize the use of the ERVs in such a way that it creates the smallest load on all other mechanical equipment possible. In addition to the use of the ERVs, I propose to use the central plant idea that was outlined briefly in the third alternative. I will extend the steam service from the University of Maryland s central steam plant. Because two of the existing systems in the building currently use steam preheat coils, there is currently steam service extended to the building. However, it is my belief that a larger service may be required than is available, so a larger line would have to be provided. This steam service will stepped down by a pressure reducing valve to the appropriate pressure and then supplied to steam preheat coils located in each of the air handling units. A larger heat exchanger will be installed to convert the steam to hot water which can be used to provide additional heat for the building. For the cooling aspect I propose to use water cooled vapor absorption chillers. By using a single stage water cooled absorption chiller, it will once again allow me to make use of the steam that is available from university s central plant. I plan to use a single stage absorption chiller because even though dual stage absorption chillers have higher efficiencies, they are also significantly more expensive. Therefore, once through the pressure reducing valve, a primary loop will be sent to the chiller while a secondary loop will be sent through the heat exchanger. Heat rejection for the chiller plant will be provided forced draft cooling towers. Additional pumps will be required to circulate these fluids throughout the facility. Base mounted end suction type pumps will be used Page 16

17 to circulate the chilled water to the cooling coils and the condenser water to the cooling towers. Vertical in line pumps will be used to circulate the hot water through the heat exchanger to the hot water reheat coils. In addition to the water side changes that are necessary to implement my proposed system, a few slight changes have to be made to the air side system. Both the supply and return fans must be increases slightly in size to overcome the additional static that is generated by the energy recovery wheels. In conjunction with these systems, I propose to use the same type of terminal devices that are being used in the facility currently. I see no benefit in changing away from VAV boxes with hot water reheat Proposal Justification It is my belief that the proposed redesign system presents a better solution to the design problem. I believe that after my analysis is complete, the proposed system will provide both environmental and financial benefits not attained by the existing system in place. It is my assumption that when both the existing system and the proposed system are compared, that the life cycle cost for the proposed system will be significantly lower than the cost of the system currently in place. The proposed system makes use of opportunities generated by the project itself, such as the existing university central steam plant, and the recovery of energy from the high amount of return and exhaust air. Also, the use of a central plant system will be easier to maintain and monitor for the staff of the university, because they are already familiar with this system as it is used in several other facilities throughout the university. All of this I hope will be shown, in addition with keeping the quality of the environment provided by the system to the level it is at now, if not better Coordination and Integration Issues The main coordination issue will be the extension and connection of the existing steam service to the facility. Providing service with adequate capacity for the requirements generated by the building is essential to my proposed system. There is an Page 17

18 existing mechanical room in the facility that has more than sufficient space for the chillers and heat exchangers that need to be installed for the proposed system. The locations of the air handling units containing the ERVs will need to be determined. Code restricts the location of these units and outlines a series of minimum distances that must be maintained from such things as exhaust fans to prevent cross contamination. Because the exhaust fans will not be relocated as part of the proposed redesign, finding the appropriate room for the air handlers will be a challenge. The are several sections of the roof that are flat which will provide space for the roof mounted mechanical equipment such as the air handling units and new cooling towers that are going to be required. The terminal units are not being changed and shall remain VAV boxes. Because of this, no additional consideration needs to be given to locating additional equipment within the spaces themselves. Therefore mechanical space within the ceilings will not be an issue. However, in making the system more uniform, several new VAV boxes will be required for spaces that were not previously equipped with them. 3.4 Financial Analysis of Existing System First Cost Analysis In order to have a method of comparison for my proposed system, I have to first establish the cost of the existing mechanical system in place. There are two components to the overall system cost: the first cost, and the annual operating cost. My first step in the process was to establish an accurate estimate of the first cost of the existing mechanical system. Major pieces of mechanical equipment including the existing rooftop units, chiller, pumps, heat exchanger, etc as well as the VAV units used as terminal devices all contribute to the first cost of the system. The schedules of existing equipment that were provided with my drawing sets were used to determine what type of equipment and what scale of equipment were present within the existing system. Taking the Page 18

19 information I gathered, I then used the RS Means guide for mechanical equipment to determine the price of each piece of existing mechanical equipment. A summary of the pieces of mechanical equipment present and their corresponding cost is provided in the table below: Table 3 First Cost of Existing Mechanical System FIRST COST OF EXISTING MECAHNICAL SYSTEM Equipment First Cost Renovation Section: AHU-1 $15, AHU-2 $29, R-1 $8, P-1 $1, P-2 $1, P-3 $5, P-4 $5, HE-1 $5, CH-1 $162, Expansion: RAC-1 $18, RAC-2 $9, RAC-3 $20, RAC-4 $18, RAC-5 $20, RAC-6 $15, CP-1 $1, CP-2 $1, Total: $342, Annual Operating Cost Analysis of Existing System A component of the over all system cost that is just as, if not more important than the system first cost is the Life Cycle Cost (LCC) of the system. The LCC takes into account all of the operating costs, such as the utilities required to operate the equipment, and maintenance costs, like filtration replacement, refrigerant recharging, etc over the service life of the equipment. While I do not have a way to simulate and take into account the typical maintenance costs, the annual cost due to utilities can be simulated by using Carrier s Hourly Analysis Program (HAP). Page 19

20 To determine the annual operating cost for the existing mechanical system at Gossett Field House, the existing facility had to be modeled in HAP. Fortunately for the purposes of this comparison, I was provided with the design inputs that the design engineer used to generate his loads which he used to select the equipment which was provided under the addition phase of the project. Unfortunately for me however, the renovation section of the project was performed by a different engineer. Therefore, the inputs that were used to generate the loads for this section of the project were unavailable to me. To develop the design inputs for this section, I referred to ASHRAE Std. 62 for the ventilation requirements for each of the spaces that I was to model as well as an estimated occupancy for each of the spaces. I also referred to ASHRAE Std to develop an appropriate wattage per square foot for the lighting load. These are typical design practices used when generating loads for a building. I also included several additional loads in these spaces other than the loads generated by occupants. For example, in each of the offices spaces, I added a separate load for a computer work station. Using these design guidelines for the renovation section, and the inputs that were used in generating the loads for the addition section, I was able to input the spaces for the building. The wall sections and windows with corresponding R-values were also put into HAP so that ASHRAE transfer functions could be used to determine the loads. An occupancy profile was put into HAP to determine when the people occupying each of the spaces would be in the building generating load. With all of this information put into HAP, a design simulation was run to determine how close the load on each of the air handlers was to what the scheduled load was. After several design simulations and adjustments, the loads generated from HAP correlated with the design loads provided in the design documents. A summary of the design loads is provided in the table below: Table 4 Load Summary for Existing System Chilled Water MBH Chilled Water GPM 650 DX Cooling MBH 1138 Steam Heat MBH 3034 Page 20

21 Gas Heat MBH 1942 Hot Water Reheat MBH 1397 Hot Water Reheat GPM 106 Total Conditioning CFM Total Cooling MBH 4398 Total Heating MBH 4431 With the design heating and cooling loads accurately generated for Gossett Field House, the energy simulation of the existing mechanical system can begin. In order to accurately simulate the energy usage for the existing mechanical system, three steps must be taken. First, all the major pieces of mechanical equipment must be put into HAP in detail. The supply and return fans which run on electricity require that their efficiencies and total static pressure be input into the program. This will help the program determine the annual energy cost required to run the fans in the building. On they hydronic side of the system, flow rates and head to overcome must be put into the program to determine the annual cost generated by pumping chilled and hot water throughout the building. The program also takes into account the cost of generating both the heating and cooling for the building annually based on the space loads that were determined during the design load simulation process. After this step has been completed, each of the spaces and pieces of equipment must be connected to the appropriate system or plant. For example, each of the spaces must be connected to its air system and the chiller must be connected to a chilled water plant with its corresponding pumps. The final step in performing the annual energy simulation and cost analysis is to input the required utility rates. At Gossett Field House, there are two types of utilities that are used. The first type of utility is electricity, which is used to power the chillers, pumps, fans, as well as the cooling mode of the DX rooftop units. The existing system also uses natural gas in direct fired combustion to provide heating in the six rooftop units that serve the additions. In addition to the natural gas required for heating, steam is also used, so a rate for the generation of steam at the universities central steam plant was also required. In order to obtain the required utility rates, I contacted Mr. John Vucci, a facilities manager at the University of Maryland who is responsible for the operation of Gossett Field House. The Page 21

22 utility rates that Mr. Vucci provided me for both electric, natural gas, and steam service are provided in the table below: Table 5 Utility Rates for Gossett Field House Electric Rate $0.65/Kwh Natural Gas Rate $8.00/Decatherm Steam $18.00/1000# Using the utility rates provided above, I was finally able to use HAP to simulate the annual energy usage and cost. A simple electric rate was used as opposed to a complex rate because, as Mr. Vucci informed me, with deregulation, no clear demand is known. The power grid demand worst five days sets the demand for the season. A customer specific demand is based upon whether the user demand is on the same day as the grid. Therefore, Mr. Vucci suggested that I used the simple rate he provided above. The building energy usage and cost was simulated using the information above combined with the space loads generated by the envelope and occupants of the building. The basic results of this simulation are listed in the table below. For detailed results of this simulation, please refer to the HAP Output for Existing System, in Appendix B. Table 6 Annual Cost Summary for Existing System Table 6.1. Annual Costs Component Gossett ($) Air System Fans 14,997 Cooling 26,721 Heating 6,759 Pumps 3,274 Cooling Tower Fans 0 HVAC Sub-Total 51,751 Lights 40,872 Electric Equipment 12,990 Misc. Electric 0 Misc. Fuel Use 0 Non-HVAC Sub-Total 53,862 Grand Total 105,613 Page 22

23 Table6.2. Annual Cost per Unit Floor Area Gossett Component ($/ft²) Air System Fans Cooling Heating Pumps Cooling Tower Fans HVAC Sub-Total Lights Electric Equipment Misc. Electric Misc. Fuel Use Non-HVAC Sub-Total Grand Total Gross Floor Area (ft²) Conditioned Floor Area (ft²) Note: Values in this table are calculated using the Gross Floor Area. Table 6.3. Component Cost as a Percentage of Total Cost Gossett Component ( % ) Air System Fans 14.2 Cooling 25.3 Heating 6.4 Pumps 3.1 Cooling Tower Fans 0.0 HVAC Sub-Total 49.0 Lights 38.7 Electric Equipment 12.3 Misc. Electric 0.0 Misc. Fuel Use 0.0 Non-HVAC Sub-Total 51.0 Grand Total Design of Proposed System Design Load Development The next step in developing a method of comparison between the existing mechanical system and my proposed system was to begin the design of my proposed system. In order to begin the design, I once again had to return to the HAP simulation program to develop loads for each of the new air handling units I was going to use. Once I had the loads I could then begin selecting the required equipment for my proposed Page 23

24 system. To develop the new set of loads for my proposed system, I made use of the loads that I had already generated for the existing system and made a series of small changes. First of all, I changed each of the air side systems from whatever system they were in the existing building, over to a chilled water AHU/VAV system. The preheat coils for each of these systems were set to steam preheat coils. The terminal devices for each of these air side systems were changed over to VAV boxes with hot water terminal reheat. Three new plants were set up, a chilled water plant, a remote hot water plant, and a remote steam plant. I decided to model the hot water plant that supplies the heating water for the reheat coils in the VAV boxes as a remote plant because it is actually being generated by steam and then to hot water by being passed through a steam to hot water heat exchanger. The final step before I could run a load simulation was to enter the energy recovery information into each of the air side systems. I decided to use both sensible and latent recovery, due to the high humidity levels that are present in that area of the country over the summer time. SEMCO TS and TE3 energy recovery wheels were used for the purpose of this project, due to the high amount of literature and applications for these wheels. Following the selection example provided in the technical guide, wheels were selected for each of the air side systems. The appropriate efficiencies were then entered into HAP and the design simulation was run. The resulting loads generated on each air handling unit are located in Appendix C of this document. A typical energy recovery wheel selection and schedule of the energy recovery wheels is provided in Appendix D. A summary table of the total building loads is provided below: Table 7 Load Summary for Proposed System Chilled Water MBH Chilled Water GPM 642 Steam Heat MBH Hot Water Reheat MBH Hot Water Reheat GPM Total Conditioning CFM Page 24

25 3.5.2 Equipment Selection for proposed system Now that I had a set of loads for my proposed system, I was able to go ahead and start selecting the equipment for it, so I could run my annual energy simulation and develop a first cost for my proposed system. I decided to start with they hydronic side of my system before moving to the air side. I began by selecting the chillers I was going to use for my proposed system. Once again, I had decided to use a steam fired, single stage absorption chillers. I decided to use two chillers in a sequenced configuration, so that both chillers would be running at part load, thus not using as much energy as a single chiller running at full load capacity. For the purpose of this redesign, I have decided to use YORK single stage, steam fired absorption chillers. The total cooling load that was generated from the load analysis performed above was 3215 MBH or 268 tons of cooling and 642 GPM of chilled water required. Sizing two chillers at 66% of the full load yielded the selection of two (2) YORK 2A4 single stage absorption chillers. A schedule of these units is provided in the table below. The full information on the chillers provided by the selection catalogue is provided in Appendix D. Table 5 Proposed Chiller Schedule Capacity Consumption Evap. Flow Evap. PD Abs/Cond Flow Abs/Cond PD (Tons) (lbs/hr) GPM (Ft WC) GPM (Ft WC) CH CH With the chiller selection made, I was able to go into HAP and fill in the required design inputs so that my chillers could be modeled as part of the annual energy summary. The chiller design inputs are provided below: Full Load LCHWT: 44 Full Load EACWT: 85 Full Load Capacity: 205 Tons Electrical Input: 5.9 KW Cooler Flow Rate: 492 GPM Page 25

26 Cooler Press Drop: 17 ft Abs/Cond Flow Rate: 740 GPM Abs/Cond Press Drop: 20 ft With the chillers selected, I moved on to the selection of the cooling towers that are required for my proposed system because the chillers I am using are water cooled. For the purpose of this redesign, I decided to use cooling towers from Baltimore Air Coil (BAC). BAC provides a free download on their website of a software program that allows you to select the cooling tower that is the most economical for your design inputs. Screen shots from this program during the actual selection of the cooling towers that are required for my proposed redesign are provided below: Figures 4&5 - Cooling Tower Selection Page 26

27 With the aide of this program I selected two (2) units, one for each chiller in my configuration. This selection allowed me to fill in several necessary design inputs in HAP for the cooling towers that are part of my chilled water plant. These design inputs include: Condenser Water Flow Rate: 740 GPM Condenser Water Pump Head: 13.7ft Full Load Fan kw: 14.9 kw Now that I had selected the chillers and corresponding cooling towers for my proposed redesign, I could fill out the information required for setting up my chilled water plant. Each of the chillers was connected to a cooling tower and the capacity information was filled in. Also at this point the head and flow values for the chilled water pumps had to be filled in. At this point I decided to select the pumps that would circulate the chilled water throughout the building. I determined the pump head to overcome was 50 ft using the equivalent length method. Then using this information, combined with the flow, I began Page 27

28 the pump selection. For the purpose of this redesign, I decided to use BELL & GOSSETT base mounted end suction pumps. I then went to the pump curves for 1510 Series centrifugal base mounted pumps. The curve used to perform the selection is provided in Appendix D. From the pump curve I selected two (2) 15104BC pumps for each chiller. I have provided for two pumps for each chiller with one pump being on stand by. Additional information on this pump selection is provided in the pump schedule below: Table 9 Proposed Chilled Water Pump Schedule GPM Head Motor Hp RPM Efficiency Type (Ft) P % Base Mounted P % Base Mounted P % Base Mounted P % Base Mounted The same process was used in the selection of the hot water circulating pumps. It was determined that the flow required for the hot water reheat coils was 142 GPM and the head to overcome was 35 ft. Using this information along with the Series 80 Bell & Gossett pump curves, I selected two (2) 803x3x7B vertical inline pumps, again with one on standby. The pump curve used in selection is provided in Appendix D, and additional information on this pump selection is provided in the schedule below: Table 10 Proposed Hot Water Pump Schedule GPM Head Motor Hp RPM Efficiency Type (Ft) P % Vertical Inline P % Vertical Inline Using this pump information and the hot water flow information, the remote hot water plant model was completed. The remote steam plant was also modeled at this point because no further equipment selection was necessary for its modeling. Page 28

29 With the sizing of the hydronic equipment for my proposed system completed, I then moved on to the sizing of the air system. The sizing of the energy recovery wheels for each of the units was performed earlier in the process in order to calculate the new design loads for the proposed system. The next step in the process was the selection of the air handling units. For the purpose of this redesign, I used YORK Curbpak outdoor built up air handling units. These air handling units are available with a variety of different options that can be put together to build an air handling unit for the particular application being designed for. The selection of the units is a multiple step process. First the unit size is determined by the coil face velocity to be maintained. York recommends that cooling coils are selected based on a 500fpm face velocity so that is what was used in determining the appropriate unit size. The next step was to choose the segments that were appropriate for the proposed application. The components that were applicable to my proposed application included supply and return fans, a mixing box, filter section, a cooling coil, and a heating coil. Then the coils were sized for each air handling unit to provide the required heating and cooling capacity to overcome the space loads. The next step was to determine the total static pressure that must be overcome by the fan within the unit. To determine the static pressure, the external static pressure generated by the ductwork, bends, and dampers downstream of the unit, was added to the static generated within the unit by the various components such as the coils and filters. Finally, using the total static pressure that was calculated and the amount of air to be distributed by each unit, the appropriate supply and return fans were selected for each of the units. Complete example unit selections, as well as a sample static pressure calculation are provided in Appendix D. An abbreviated air handling unit schedule is provided below: Table # - Proposed AHU Schedule FAN COOLING HEATING (MBH) (MBH) CFM OA CFM ESP (IN. WC) AC AC RAC Page 29

30 RAC RAC RAC RAC RAC With the selection of the air handling units, the design of my proposed system was complete. I could now generate a method of comparison between the existing and my proposed system through financial means. Again I will look at two components, the initial first cost of my proposed system and the over all life cycle cost of my proposed system. Then comparisons will be drawn based on this financial information as to which system would be the most economical over the life cycle of the system. 3.6 Financial Analysis of Proposed System First Cost Analysis of Proposed System Again the initial step I took in the financial analysis of my proposed system was to generate a first cost estimate for the system. Using RS Means once more as my estimating guide, I priced the individual pieces of mechanical equipment based upon the selections made and schedules that were generated in the design of the proposed system. I anticipated an increase in first cost because of the addition of several pieces of equipment, including additional chillers, pumps, and ERVs. The first cost estimate for my proposed system is provided below: Table 12 - First Cost of Proposed System FIRST COST OF PROPOSED MECAHNICAL SYSTEM Air Side Equipment: Equipment First Cost AHU-1 $20, ERV-1 $15, AHU-2 $27, Page 30

31 Water Side Equipment: ERV-2 $26, RAC-1 $15, ERV-3 $11, RAC-2 $4, ERV-4 $6, RAC-3 $11, ERV-5 $9, RAC-4 $10, ERV-6 $8, RAC-5 $14, ERV-7 $9, RAC-6 $5, ERV-8 $7, CH-1 $149, CH-2 $149, P-1 $2, P-2 $2, P-3 $2, P-4 $2, P-5 $1, P-6 $1, HE-1 $6, CT-1 $11, CT-2 $11, Total: $547, As expected, the first cost of my proposed system is higher. However, there are additional first cost considerations to be taken into account. RS Means provides an amount of ductwork that should be provided for a particular system per ton of air conditioning that is to be provided. Because my proposed system requires less tons to condition the space, less ductwork will also be required. Calculations for the ductwork savings are provided in the table below: Table 13 - Ductwork Savings for Proposed System Difference in Tons between systems 98.6 Lbs of ductwork per ton of air conditioning 240 Price per lb of galvanized steel ductwork $5.45 Total Ductwork Savings $128,900 Page 31

32 Annual Operating Cost Analysis of Proposed System With the changes to the system made, and all the design elements completed, the new proposed system was once again modeling using Carrier s HAP program. The same utility rates were used as were used in the simulation of the existing system. The only changes made to the simulation were those outlined in the design of the proposed system. A brief summary of the annual operating cost as produced by the HAP simulation is provided below. For a more detailed breakdown of the energy usage for the proposed system, refer to Appendix E. Table 14 - Annual Cost Summary for Proposed System Table Annual Costs Component Gossett ($) Air System Fans 13,439 Cooling 17,942 Heating 3,796 Pumps 2,281 Cooling Tower Fans 3,324 HVAC Sub-Total 40,782 Lights 40,872 Electric Equipment 12,990 Misc. Electric 0 Misc. Fuel Use 0 Non-HVAC Sub-Total 53,862 Grand Total 94,644 Table Annual Cost Per Unit Floor Area Component Gossett ($/ft²) Air System Fans Cooling Heating Pumps Cooling Tower Fans HVAC Sub-Total Lights Electric Equipment Misc. Electric Misc. Fuel Use Non-HVAC Sub-Total Grand Total Page 32

33 Table Component Cost as a Percentage of Total Cost Gossett Component ( % ) Air System Fans 14.2 Cooling 19.0 Heating 4.0 Pumps 2.4 Cooling Tower Fans 3.5 HVAC Sub-Total 43.1 Lights 43.2 Electric Equipment 13.7 Misc. Electric 0.0 Misc. Fuel Use 0.0 Non-HVAC Sub-Total 56.9 Grand Total Comparison and Summary At the outset of my thesis work, it was my hypothesis that my proposed system of chilled water air handlers and energy recovery wheels would be a more economical solution than the current system of packed units with DX cooling and direct fired gas heating. As was expected, the first cost of my proposed system was significantly higher than the first cost of the existing system that is in place. However, other first cost considerations were taken into account. My proposed system decreased the heating and cooling loads, as well as the amount of air required to meet these loads. Because of this reduction, there was a first cost savings from the amount of ductwork that needed to be installed in the building. This substantially closed the gap between the first costs of the two systems. Annual operating costs were also taken into account to help generate the life cycle cost of each system. Upon reviewing each of these simulations, there was a significant drop in cost when switching to my system as I had expected. A comparison summary between the existing system and the proposed system is provided in the table below: Page 33

34 Existing System Proposed System Difference between Existing and Proposed Cooling MBH 4, , ,182.8 Heating MBH 4, , ,234.3 Reheat MBH 1, , Design CFM 86,625 77, First Cost $342,600 $547, ,400 Ductwork Savings - - $128,900 - $128,900 Annual Operating Cost $51,751 $40,782 - $10,969 In order to determine the most accurate cost of each system, a life cycle cost analysis was performed. According to ASHRAE, the service life of air handling units is 15 years, so a 15 year period was used for the purpose of the life cycle analysis. The interest rate tables were used from Engineering Economic Analysis to determine the present value of the annual operating cost over a 15 year period. To determine the appropriate interest rate, I first took into consideration that inflation is 3%. Then referencing the current US prime interest rate, I determined an interest rate of 5% would be appropriate. Then, using the interest rate of 5%, I used the present given annual multiplier for a 15 year period to calculate the operating cost over the 15 year period. This value along with the first cost considerations equals the overall cost of the system over its service life. The life cycle cost, first cost, and total cost for each system is provided in the table below: Table 15 Total Cost Comparison Existing System Proposed System First Cost $342,600 $418,100 Life Cycle Cost $537,160 $423,305 Total $879,760 $841,405 Page 34

35 After the life cycle cost of each system was calculated, and the system first cost was added for each system, the total cost of each system was calculated. According to my calculations, the proposed system would have saved the University of Maryland approximately $38,500 over the service life of the mechanical equipment. That is a savings of $2600 per year. The life cycle analysis of both the existing system and proposed system confirmed my initial belief that while the initial installation cost of the proposed system would be more expensive, the energy savings generated, over the service life of the equipment would lead to a lower total cost for the system. Page 35

36 4 Impact of Proposed Mechanical System on Structure 4.1 Structural Impact The redesign of the proposed mechanical system will have a significant impact on the building structural system. With the addition of various air handler unit sections, and energy recovery wheels, the units provided under the proposed mechanical redesign would weigh more than the packaged units that are currently located on the roof. Therefore the structural support system should be redesigned. The current roof of Gossett Field House is a flat concrete slab, so room for the proposed mechanical equipment will not be a problem. The existing roof design consists primarily of W- shaped structural steel members with open web steel joists used in limited capacity. 4.2 Redesign Parameters When investigating the current design of the structural system at Gossett Field House, it was determined that the BOCA code was the building code used for the project. Upon reviewing the code, for structural design the BOCA code referenced ASCE-7 as its structural code. For the purposes of this redesign, the design values provided by the code will be used in selecting the appropriate members. Also, because W-shaped structural steel members were the basis of the original design, I will continue to use them for the structural redesign. A list of the design loading values outlined in the code that will be used in the redesign of the structural system is outlined in the table below: Table 16 Structural Design Loads Loading Case Value Roof Live Load From ASCE Section psf Roof Snow Load Ground Snow Load 20psf Flat Roof Snow Load 16.1psf Page 36

37 Snow Exposure Factor 1.0 Snow Load Importance 1.1 Thermal Factor 1.0 Super Imposed Load 30psf 4.3 Structural Redesign In order to being the structural redesign, first the weights of the new air handling units had to be determined. This was done by taking each of the segment sections for each air handler and adding them together to determine the overall weight of the unit. The dimensions of the unit were determined in the same way, adding the length of each section together to determine the over all length of the unit. The units will be centered in each bay, so the tributary width on both sides will be equal. For the purpose of this redesign, the beams supporting RAC-1 thru RAC-6 will be designed. Of the six units, there are only three individual cases, because there are two each of the 065 units, two of the 170, and two of the 215. Once again ASCE-7 was referred to in order to generate the loads provided by the air handling units. According to section 2.3 Combined factored loads using strength design, a roof load is determined using the total dead load added to the roof live load or the roof snow load, whichever load provides the worst loading case. Because the roof life load is higher than the roof snow load, it will be used in the calculation of the total load. In addition there are several formulas used in the calculation of loads as well as serviceability factors such as deflection. The formulas used for this redesign are provided below: Dead Load = Load of AHU + Super imposed dead load Total Load = 1.2(Dead Load) + 0.5(Roof Live Load) Total Deflection = L/180 Deflection from Live Load = L/240 Mmax = W(L^2)/8 Vmax = W(L)/2 Page 37

38 For the purpose of this redesign, members will be designed for the long side of each of the air handling units, with one member being designed for each side of the width of the unit. For a table of the structural calculations performed, refer to Appendix F. The members selected via these calculations are a W12X19 for the 056 units, a W12x22 for the 170 units, and W14x22 for the 215 units. The beams sizes that have been produced by my structural calculations have been calculated using gravity loads. Wind and seismic loading was not taken into account when generating the new beam sizes for the proposed mechanical system. Because these loads were taken into account throughout the rest of the existing structural design, I felt there was no need to account for these loads in the redesign of the roof structure. No vibration control analysis was performed. Because vibration control will be provided by resilient mounts and the air handling units will be isolated from the structure, I deemed it unnecessary to perform such an analysis. Also, the units have been downsized, with smaller fans which would produce less vibration than the existing units, another reason why a vibration analysis was not performed. 4.4 Structural Redesign Conclusions After performing the structural calculations necessary to size support beams for the air handling units proposed under the mechanical redesign conclusion, it is my belief that the redesigned structure will not have a significant impact on cost or schedule. Because the size of the structural members selected is similar to the size of the existing structural members present, I feel that no significant cost increase or decrease will be developed with the new members required for the proposed air handling units. Page 38

39 5 Impact of Proposed Mechanical System on Electrical System 5.1 Electrical Panel Board Analysis The existing mechanical system for Gossett Field House contains several pieces of equipment that require electrical service. As such electrical distribution for these pieces of equipment is handled by several panel boards. Because the work done at Gossett Field House involved both renovation of the existing facility and an expansion, the mechanical equipment load is not organized or concentrated on the panel boards. The mechanical system outlined in the mechanical redesign section of this report makes significant changes to the electrical loads provided by the mechanical equipment. The single chiller currently in place was replaced by two new chillers. The packaged rooftop units were replaced with built up air handling units. Energy recovery wheels were added to each of the u nits, and cooling towers provided additional electrical load. With the proposed system replacing or generating new loads, an electrical analysis of the changes was performed. With the new loads being added, a panel board redesign to concentrate the mechanical loads seemed like a logical step. Therefore I decided to redesign the panel boards serving the mechanical equipment. 5.2 Mechanical Equipment Loads The first step in the redesign of the electrical panel boards was to determine the electrical load generated from each of the major pieces of mechanical equipment. I referred back to the literature for each of the pieces of equipment to determine the electrical load. The electrical load for each of the new pieces of mechanical equipment is provided in the table below: Page 39

40 Table 17 - Electrical Load Generated by Proposed Mechanical Equipment Equipment Voltage/Phase FLA KVA ERV-1 480/ ERV-2 480/ ERV-3 480/ ERV-4 480/ ERV-5 480/ ERV-6 480/ RAC-1 480/ RAC-2 480/ RAC-3 480/ RAC-4 480/ RAC-5 480/ RAC-6 480/ Panel Board Design With the electrical loads generated by the proposed mechanical equipment determined, the layout of the panel boards could begin. From the initial development of the loads, it was my assumption that one if not two 480/77 panel boards would be required for the mechanical equipment. The loads were then laid out on the panel boards. It is important to keep close to equal loads on each phase to avoid any load being conducted through the ground wire. The panel board layouts for the loads generated by the proposed mechanical equipment are provided in Appendix F Electrical Impact Conclusions Once the equipment was laid out on the panel boards, it became apparent that another panel board would be required for the energy recovery wheels. This would add one more panel board than the original design had and would add first cost to the project. Page 40

41 However, because only one additional panel board was required, it is my conclusion that the proposed mechanical system, while having significantly different loads than the existing mechanical system, would not have a substantial effect on the electrical system first cost. Page 41

42 6 - Design Summary 6.1 Mechanical Summary At the outset of my thesis work, it was my hypothesis that my proposed system of chilled water air handlers and energy recovery wheels would be a more economical solution than the current system of packed units with DX cooling and direct fired gas heating. As was expected, the first cost of my proposed system was significantly higher than the first cost of the existing system that is in place. However, other first cost considerations were taken into account. My proposed system decreased the heating and cooling loads, as well as the amount of air required to meet these loads. Because of this reduction, there was a first cost savings from the amount of ductwork that needed to be installed in the building. This substantially closed the gap between the first costs of the two systems. Annual operating costs were also taken into account to help generate the life cycle cost of each system. Upon reviewing each of these simulations, there was a significant drop in cost when switching to my system as I had expected. A comparison summary between the existing system and the proposed system is provided in the table below: Existing System Proposed System Difference between Existing and Proposed Cooling MBH 4, , ,182.8 Heating MBH 4, , ,234.3 Reheat MBH 1, , Design CFM 86,625 77, First Cost $342,600 $547, ,400 Ductwork Savings - - $128,900 - $128,900 Page 42

43 Annual Operating Cost $51,751 $40,782 - $10,969 In order to determine the most accurate cost of each system, a life cycle cost analysis was performed. According to ASHRAE, the service life of air handling units is 15 years, so a 15 year period was used for the purpose of the life cycle analysis. The interest rate tables were used from Engineering Economic Analysis to determine the present value of the annual operating cost over a 15 year period. To determine the appropriate interest rate, I first took into consideration that inflation is 3%. Then referencing the current US prime interest rate, I determined an interest rate of 5% would be appropriate. Then, using the interest rate of 5%, I used the present given annual multiplier for a 15 year period to calculate the operating cost over the 15 year period. This value along with the first cost considerations equals the overall cost of the system over its service life. The life cycle cost, first cost, and total cost for each system is provided in the table below: Existing System Proposed System First Cost $342,600 $418,100 Life Cycle Cost $537,160 $423,305 Total $879,760 $841,405 After the life cycle cost of each system was calculated, and the system first cost was added for each system, the total cost of each system was calculated. According to my calculations, the proposed system would have saved the University of Maryland approximately $38,500 over the service life of the mechanical equipment. That is a savings of $2600 per year. The life cycle analysis of both the existing system and proposed system confirmed my initial belief that while the initial installation cost of the proposed system would be more expensive, the energy savings generated, over the service life of the equipment would lead to a lower total cost for the system. Page 43

44 6.2 Structural Design Summary After performing the structural calculations necessary to size support beams for the air handling units proposed under the mechanical redesign conclusion, it is my belief that the redesigned structure will not have a significant impact on cost or schedule. Because the size of the structural members selected is similar to the size of the existing structural members present, I feel that no significant cost increase or decrease will be developed with the new members required for the proposed air handling units. 6.3 Electrical Design Summary Once the equipment was laid out on the panel boards, it became apparent that another panel board would be required for the energy recovery wheels. This would add one more panel board than the original design had and would add first cost to the project. However, because only one additional panel board was required, it is my conclusion that the proposed mechanical system, while having significantly different loads than the existing mechanical system, would not have a substantial effect on the electrical system first cost. Page 44

45 List of Figures Figures 1 Location of College Park, MD Figures 2 & 3 Gossett Field House Figures 4 & 5 Cooling Tower Selection Page 45

46 List of Tables Table 1 Existing Air Handling Unit Schedule Table 2 Existing Packaged Unit Schedule Table 3 First Cost of Existing Mechanical System Table 4 Load Summary for Existing System Table 5 Utility Rates for Gossett Field House Table 6 Annual Cost Summary for Existing System Table 7 Load Summary for Proposed System Table 8 Proposed Chiller Schedule Table 9 Proposed Chilled Water Pump Schedule Table 10 Proposed Hot Water Pump Schedule Table 11 Proposed AHU Schedule Table 12 First Cost of Proposed System Table 13 Ductwork Savings for Proposed System Table 14 Annual Cost Summary for Proposed System Table 15 Total Cost Comparison Table 16 Structural Design Loads Table 17 Electrical Load Generated by Proposed Mechanical Equipment Page 46

47 Works Cited American Institute of Steel Construction, Inc. (2001). Manual of Steel Construction: Load and Resistance Factor Design (Third Edition). American Society of Heating Refrigeration, and Air Conditioning Engineers, Inc. (1999). Standard : Energy Standards for Buildings Except Low-Rise Residential Buildings. American Society of Heating Refrigeration, and Air Conditioning Engineers, Inc. (2001). Standard : Ventilation for Acceptable Indoor Air Quality. American Society of Heating Refrigeration, and Air Conditioning Engineers, Inc. (2003). ASHRAE Handbook: Applications American Society of Heating Refrigeration, and Air Conditioning Engineers, Inc. (2003). ASHRAE Handbook: Fundamentals Baltimore Air Coil Incorporated BAC, Inc. (2005) Bell & Gossett Incorporated B&G, Inc. (2005) Lindeburg, Michael R. (2001) Engineering Economic Analysis: An Introduction. Belmont, CA: Professional Publications, Inc. Mossmann, Melville J. (2005) RS Means Mechanical Cost Data, MA: RS Means Construction Publishers and Consultants. National Fire Protection Association. (2001) National Electric Code: USA: Delmar. Semco Incorporated. Semco, Inc. (2005) York International. York International Corp Page 47

48 Appendix A Existing Mechanical Equipment Schedules Air Cooled Liquid Chiller Schedule Capacity GPM Compressor EWT LWT Evap. PD (Tons) KW ( F) ( F) (Ft WC) CH Steam to Water Heat Exchanger Schedule Steam GPM Steam Pres. EWT LWT Pres Drop Lbs./Hour PSI ( F) ( F) (Ft WC) HE Pump Schedule GPM Head Motor Hp RPM Type (Ft) P Vertical In-line P Vertical In-line P Base Mounted P Base Mounted Page 48

49 Appendix B HAP Simulation Outputs for Existing System (Information begins on the next page) Page 49

50 Table 1. Annual Costs Component Gossett ($) Air System Fans 14,997 Cooling 26,721 Heating 6,759 Pumps 3,274 Cooling Tower Fans 0 HVAC Sub-Total 51,751 Lights 40,872 Electric Equipment 12,990 Misc. Electric 0 Misc. Fuel Use 0 Non-HVAC Sub-Total 53,862 Grand Total 105,613 Table 2. Annual Cost per Unit Floor Area Gossett Component ($/ft²) Air System Fans Cooling Heating Pumps Cooling Tower Fans HVAC Sub-Total Lights Electric Equipment Misc. Electric Misc. Fuel Use Non-HVAC Sub-Total Grand Total Gross Floor Area (ft²) Conditioned Floor Area (ft²) Note: Values in this table are calculated using the Gross Floor Area. Table 3. Component Cost as a Percentage of Total Cost Gossett Component ( % ) Air System Fans 14.2 Cooling 25.3 Heating 6.4 Pumps 3.1 Cooling Tower Fans 0.0 HVAC Sub-Total 49.0 Lights 38.7 Electric Equipment 12.3 Misc. Electric 0.0 Misc. Fuel Use 0.0 Non-HVAC Sub-Total 51.0 Grand Total Page 50

51 Air System Fans 14.2% 10.3%Electric Equipment Cooling 25.3% 40.7% Lights Heating 6.4% Pumps 3.1% 1. Annual Costs Component Annual Cost ($) ($/ft²) Percent of Total (%) Air System Fans 14, Cooling 26, Heating 6, Pumps 3, Cooling Tower Fans HVAC Sub-Total 51, Lights 40, Electric Equipment 12, Misc. Electric Misc. Fuel Use Non-HVAC Sub-Total 53, Grand Total 105, Note: Cost per unit floor area is based on the gross building floor area. Gross Floor Area ft² Conditioned Floor Area ft² Page 51

52 HVAC Electric 42.6% 51.0% Non-HVAC Electric HVAC Natural Gas 6.4% 1. Annual Costs Component HVAC Components Annual Cost ($/yr) ($/ft²) Percent of Total (%) Electric 44, Natural Gas 6, Fuel Oil Propane Remote Hot Water Remote Steam Remote Chilled Water HVAC Sub-Total 51, Non-HVAC Components Electric 53, Natural Gas Fuel Oil Propane Remote Hot Water Remote Steam Non-HVAC Sub-Total 53, Grand Total 105, Note: Cost per unit floor area is based on the gross building floor area. Gross Floor Area ft² Conditioned Floor Area ft² Page 52

53 Appendix C HAP Design Outputs for Proposed System Air System Information Air System Name... AC-1 Equipment Class... CW AHU Air System Type... VAV Number of zones Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Jul CFM Max block CFM at Jul CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Jul 1500 OA DB / WB / 75.0 F Entering DB / WB / 63.2 F Leaving DB / WB / 50.5 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check of 29 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Jul CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Page 53

54 Air System Information Air System Name... AC-2 Equipment Class... CW AHU Air System Type... VAV Number of zones Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Aug CFM Max block CFM at Aug CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Aug 1500 OA DB / WB / 75.0 F Entering DB / WB / 62.9 F Leaving DB / WB / 50.5 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check of 50 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Aug CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

55 Air System Information Air System Name... RAC-1 Equipment Class... CW AHU Air System Type... VAV Number of zones... 1 Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Aug CFM Max block CFM at Aug CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Aug 1500 OA DB / WB / 75.0 F Entering DB / WB / 63.8 F Leaving DB / WB / 53.2 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check... 1 of 1 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Aug CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

56 Air System Information Air System Name... RAC-2 Equipment Class... CW AHU Air System Type... VAV Number of zones... 9 Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Jul CFM Max block CFM at Jul CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Jul 1300 OA DB / WB / 74.5 F Entering DB / WB / 63.7 F Leaving DB / WB / 53.3 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check... 0 of 9 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Jul CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

57 Air System Information Air System Name... RAC-3 Equipment Class... CW AHU Air System Type... VAV Number of zones Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Jul CFM Max block CFM at Jun CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Jul 1400 OA DB / WB / 74.8 F Entering DB / WB / 63.0 F Leaving DB / WB / 51.3 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check... 8 of 13 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Jun CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

58 Air System Information Air System Name... RAC-4 Equipment Class... CW AHU Air System Type... VAV Number of zones... 1 Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Jul CFM Max block CFM at Jul CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Jul 1400 OA DB / WB / 74.8 F Entering DB / WB / 64.8 F Leaving DB / WB / 53.2 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check... 0 of 1 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Jul CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

59 Air System Information Air System Name... RAC-5 Equipment Class... CW AHU Air System Type... VAV Number of zones Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Jul CFM Max block CFM at Jul CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Jul 1500 OA DB / WB / 75.0 F Entering DB / WB / 64.5 F Leaving DB / WB / 52.1 F Coil ADP F Bypass Factor Resulting RH % Design supply temp F Zone T-stat Check of 16 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Jul CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person

60 Air System Information Air System Name... RAC-6 Equipment Class... CW AHU Air System Type... VAV Number of zones... 1 Floor Area ft² Location... Baltimore, Maryland Sizing Calculation Information Zone and Space Sizing Method: Zone CFM... Peak zone sensible load Space CFM... Individual peak space loads Calculation Months... Jan to Dec Sizing Data... Calculated Central Cooling Coil Sizing Data Total coil load Tons Total coil load MBH Sensible coil load MBH Coil CFM at Sep CFM Max block CFM at Sep CFM Sum of peak zone CFM CFM Sensible heat ratio ft²/ton BTU/(hr-ft²) Water 10.0 F rise gpm Load occurs at... Sep 1000 OA DB / WB / 69.5 F Entering DB / WB / 47.3 F Leaving DB / WB / 35.2 F Coil ADP F Bypass Factor Resulting RH... 0 % Design supply temp F Zone T-stat Check... 1 of 1 OK Max zone temperature deviation F Preheat Coil Sizing Data No heating coil loads occurred during this calculation. Supply Fan Sizing Data Actual max CFM at Sep CFM Standard CFM CFM Actual max CFM/ft² CFM/ft² Outdoor Ventilation Air Data Design airflow CFM... 0 CFM CFM/ft² CFM/ft² Fan motor BHP BHP Fan motor kw kw Fan static in wg CFM/person CFM/person Page 60

61 Appendix D Equipment Selections and Selection Examples for Proposed System Enthalpy Wheel Selection Example and Schedule For the purpose of this example, the enthalpy wheel will be selected for RAC-1. The following table provides the design conditions that were used to select the wheel: Supply Air CFM 9,200 Return Air CFM 7,200 Outdoor Air Conditions: Temperature F 93 Moisture Content gr/lb Enthalpy BTU/lb 42.9 Return Air Conditions: Temperature F 75 Moisture Content gr/lb 64 Enthalpy BTU/lb 28 Purge Pressure difference in wg 2.5 Step 1 The first step is to select the wheel based on supply air, return air, and face velocity of the air on the wheel. The chart below is used to select the wheels. Wheel efficiency is maximized between fpm. Page 61

62 Using the return volume of 7,200 cfm we select a TE3-9 wheel from the chart. This will yield a face velocity of approximately 740fpm. At this face velocity, and this volume of air, the wheel will produce 0.76 in wg of static pressure. Step 2 The next step is to determine the wheel effectiveness. This is done by using the supply air to return air ratio, in this case 0.78 and the calculated face velocity. Using this information, and the chart below, we are able to determine the effectiveness of this wheel is 83% Step 3 The next step is to calculate the wheel performance. With the wheel effectiveness determined in the step above, the following formulas are used to determine the performance of the wheel: Dry bulb temperature X = 93 [.83(7200/9200)(93-75)] X = 81.3 F Page 62

63 Humidity Ratio X = [.83(7200/9200)( )] X = 87.2 gr/lb Enthalpy X = 42.9 [.83(7200/9200)( )] X = 33.2 BTU/lb Step 4 The final step is to determine the purge volume for the wheel. This volume of air is constantly removed from the wheel to prevent any kind of cross contamination. The purge volume is determined by the outdoor air to exhaust air pressure difference and the size of the wheel itself. Using the chart provided below, we determine the purge volume for this wheel is 800cfm. Energy Recovery Wheel Schedule ERV # Corresp Unit Wheel Size Efficiency Purge cfm Static inwg ERV-1 AC-1 TE % ERV-2 AC-2 TE % ERV-3 RAC-1 TE3-9 83% ERV-4 RAC-2 TE3-3 83% ERV-5 RAC-3 TE3-9 82% ERV-6 RAC-4 TE3-5 87% ERV-7 RAC-5 TE3-9 83% ERV-8 RAC-6 TE3-3 83% Page 63

64 AHU Selection Example For the purpose of this example and air handling unit to take the place of RAC-1 will be selected. Step 1 Is to select the unit size. This is done by dividing the dividing the supply cfm by the maximum coil velocity. York recommends a face velocity of 500 fpm for cooling coils so that is the velocity used. Coil area = 9200/500 = 18.4 Select Unit Size 215 Step 2 Select the appropriate sections for your unit. In this case we will select a supply fan section, a cooling coil, a heating coil, an angled filter, mixing box, and a return fan. Step 3 Select the coils for to meet the corresponding heating and cooling loads. In this case, for the cooling coil it is a 4row/10fpi and for the heating coil it is 1 row/8fpi. Step 4 Determine the total static pressure. York provides static pressure tables for each of the air handling components, using these tables along with the face velocity which is determined by dividing the cfm of the unit by the area of the component, a static value for that component is generated. The sum of the components as well as the down stream external static pressure is the total static that must be over come by the fan. The static pressure calculation for this unit is provided in the table below: Supply Return Enthalpy Purge CFM 800 Supply Air CFM 9200 OA Opening 0.04 EA Opening 0.17 SA Opening 0.08 RA Opening 0.20 Angled Filter Enthalpy Wheel Cooling Coil 0.47 Heating Coil 0.12 Total Internal Static Pressure External Static Pressure Total Static Pressure Fan size Step 5 From the calculated static pressure, use the appropriate fan table to determine the BHP and RPM to size the fan motor. Using the table provided below, it is determined the supply fan should run at 1095 RPM and 8.63BHP. Adding an additional 6% for drive losses, the BHP increases to Select a 10 hp motor for the supply fan. The same procedure is used for the return fan, yielding a 5 Hp motor. Page 64

65 Chiller Selection Table Page 65

66 Base Mounted and Vertical Inline Pump Selection Curves Page 66