Off the Grid A Home Energy Audit And Alternative Energy Feasibility Study. Final Report

Transcription

1 Off the Grid A Home Energy Audit And Final Report Document Revision #: 1.1 Date of Issue: Project Manager: Steven Dyck Supervisor: Dr. S. Nandi In partial fulfillment of the requirements of the ELEC499 Design Course and University of Victoria B.Eng Degree

2 EXECUTIVE SUMMARY The general public had customarily thought of alternative energy as science fiction, especially when it came to residential applications. Only homes of the future utilized solar, wind or geothermal energy. This project was undertaken to serve as an example to the general public of the reality of alternative energy in the residential sector. If people could be convinced that solar and geother mal technologies are viable and cost effective then we could reduce the energy demands of our nation as well as Green House Gas emissions. This report outlines the benefits of conducting a home energy audit, and utilizing alternative energies. The results show that most changes to a home can be recovered within 0-30 years. While this may not sound appealing to some homeowners, it will to those that are willing to make the investment and make an effort to reduce their Green House Gas emissions. The result of the energy analysis shows that there is room for improvement with the house envelope. The simplest upgrades included increasing the ceiling insulation and reducing the infiltration by 5%. These upgrades would see positive returns after only 1 years. Reduction in energy use has always been the best and most cost effective way to reduce utility bills. By reducing showers by one minute and 1L/min, reducing faucets by 1L/min, and toilets by L/flush, the annual savings would be $93. This upgrade would only cost $50 so the time to positive returns is only 0.54 years. Reducing the heating load by installing a programmable thermostat and turning down the heat when you are not home would cost $45. The savings would be $57 per year. It would save approximately 0.50 t co/yr of GHG emissions per year and take 0.84 years to see positive returns. A solar heated domestic hot water system that produced 59% of the daily hot water needs would cost $4,000, but it would save $60 anually. The annual Green Hous e Emission reduction would be 1.06 t CO/yr. and take 14.6 years to see positive returns. The end result of this report shows that the technology is progressing to a point where it is becoming affordable for residential homeowners to start adopting alternative energies. The more demand created for alternative energy components, the cheaper and more efficient the products will become. i

3 TABLE OF CONTENTS EXECUTIVE SUMMARY...I 1. ACKNOWLEDGMENTS TEAM MEMBERS EXTERNAL SOURCES INTRODUCTION BACKGROUND MOTIVATION PROBLEM DEFINITION AND PROJECT GOALS DISCUSSION HOME ENERGY AUDITS ALTERNATIVE ENERGY FEASIBILITY STUDIES OTHER OPTIONS SOFTWARE ANALYSIS REPORT CONCLUSIONS REFERENCES...17 APPENDIX A - SOLAR HEATED DOMESTIC HOT WATER STUDY...A APPENDIX B - GENERATING ELECTRICITY WITH PHOTOVOLTAIC CELLS...B STUDY APPENDIX C - ACTIVE SOLAR SPACE HEATING STUDY...C APPENDIX D - GEOTHERMAL SPACE HEATING STUDY...D APPENDIX E - BUILDING BLUE PRINTS...E APPENDIX F - PROGRESS REPORT #1...F APPENDIX G - PROGRESS REPORT #...G ii

4 TABLE OF FIGURES FIGURE 3..1 AVERAGE DAILY INSOLATION WHILE VARYING COLLECTOR AZIMUTH... 6 FIGURE 3.. YEARLY INSOLATION WHILE VARYING COLLECTOR AZIMUTH... 7 FIGURE 3..3 AVERAGE DAILY INSOLATION WHILE VARYING COLLECTOR TILT... 7 FIGURE 3..4 YEARLY INSOLATION WHILE VARYING COLLECTOR TILT... 8 FIGURE 3..5 PASSIVE SOLAR ANALYSIS OF SOUTHERN WINDOWS...11 FIGURE 3..6 SUN ANGLES DURING THE YEAR...11 iii

5 1. ACKNOWLEDGMENTS 1.1 Team Members This project was conceived and conducted by Steven Dyck. He is a 4 th year student at the University of Victoria in the Electrical Engineering Department. His specialization is in electronics with an emphasis on embedded systems. 1. External Sources I would like to acknowledge the following people who gave of their time and experience during the course of this project: Dr. V. Ismet Ugursal and Dr. Mehmet Yildiz for helping with the thermodynamics portion of this project and Dr. S. Nandi for agreeing to supervise the project. Thank you for your support in making this project a success.. INTRODUCTION.1 Background The general public has long thought of alternative energy as science fiction, especially with residential applications. Only homes of the future utilized solar, wind or geothermal energy. But the steady increasing costs of fossil fuels and decreasing resources are causing people to take a second look at alternative energies. Solar homes are being built all over North America. Communities are being developed with geothermal space heating systems. Even owners of existing homes are taking notice and upgrading their homes with solar heated domestic hot water or passive solar space heating systems. Homeowners are also beginning to understand the importance of insulation and energy efficient appliances. While many options are more cost effective when the home is being built, there are still many cost effective options for existing homes. The original intention of this project was to take an existing home and explore the possibility of completely removing it from the electrical and natural gas public utility grid. After a brief preliminary study, this was determined to be an inefficient use of resources. The costs involved would have taken the homeowners over 40 years to see positive returns and cost nearly $100,000. Since this is only a possibility for a very small portion of homeowners, the project was adjusted to only augment the home with alternat ive energy sources instead of replacing existing conventional energy sources.. Motivation This project was undertaken for several reasons. Industrialized society is slowly warming up the planet with its Green House Gas (GHG) emissions that are having a disastrous effect on the environment. Polar ice caps are melting, ocean front property is disappearing due to tectonic plate tilting and the ocean itself is warming up. While this cannot be changed over night, if everyone does their part, GHG emissions can be substantially reduced. This project was also undertaken to serve as an example to the general public of the reality of alternative energy in the residential sector. If people could be convinced that solar and geothermal technologies were within their reach it would create a market demand to bring down the high initial cost, as well as, reduce GHG emissions. There is an opportunity to increase the cleanliness of our environment through a substantial reduction in energy usage in the residential market. In a two-pronged upgrade, residential homes could reduce their GHG emission contribution by as much as 13 tonnes of CO per year 1. This upgrade would be a combination of energy saving renovations as well as alternative energy installations. 1 Based on avoiding 4.7 MWh of electricity for domestic hot water (3.8 tco/yr), 6.MWh of electricity for space heating (4.0 t CO/yr) and 11MWh of electricity for appliances, lightings, etc (5. t CO/yr). 1

6 .3 Problem Definition and Project Goals The majority of homeowners are not aware of the potential and possibilities that are provided by alternative energies. Many are not even aware of the cost and comfort savings that home energy audits can provide. It is the goal of this project to provide the following services: Conduct a complete home energy analysis to allow residential homeowners to make an informed choice on energy efficiency upgrades; Provide sound financial advice on all options given to the homeowners; Provide options for utilizing alternative energy sources for domestic hot water, space heating and possibly electrical needs; and Educate homeowners on how they can contribute to reducing Green House Gas emissions and their utility bills without sacrificing comfort. The project will be conducted on a real home in Sidney, British Columbia, Canada. Their energy consumption and usage patterns will be analyzed to determine the cost effectiveness of any potential upgrades. This project will attempt to serve as an algorithm for determining upgrading options for residential homes as well as options for integrating alternative energy systems to reduce a homes reliance and consumption of public utilities. Solar space heating, solar heated domestic hot water, geothermal space heating and cooling as well as generating electricity with photovoltaic cells will be examined to show their ability to reduce annual utility costs. Wind power will be addressed in this report, but only to show that it is not an efficient use of a homeowner s money. Passive solar heating and cooling will also be addressed. 3. DISCUSSION The project can be broken into 3 main sections: the home energy audit, the analysis and adoption of alternative energies and a software package to help the homeowner chose the right package for their requirements and financial situation. 3.1 Home Energy Audits The home energy audit will be explained in detail, including why the energy audit is conducted, the method used to conduct the audit, an explanation of the results of the audit and how to implement the findings of the audit Why Conduct Home Energy Audits There are three driving forces behind home energy audits: make the home more comfortable, reduce the home s Green House Gas (GHG) emissions (including those created by the generation of the electricity it consumes) and reduce the annual utility costs. This can be done mainly through conservation and renovation. In many cases, minor adjustments to the occupant s routines and small one-time investments can significantly reduce GHG emissions as well the home s utility costs. Such improvements include low -flow showerheads, faucets and toilets; programmable thermostats; and sealing window and doors. Other improvements involve a much higher initial cost, but in most cases the benefits and savings justify the investment Performing the Energy Audit The first step in analyzing the home envelope is to determine its heating and cooling characteristics of the home. This is done by determining the heat flow out of (or into in the case of cooling) the home. Heat transfer is made up of conduction (heat passing through the walls, windows, etc), convection (heat being drawn off the home due to wind) and radiation (not a large portion of a home s heat loss and therefore won t be considered in this model). These losses make up the skin losses. Other losses are due to infiltration (air being blown into or drawn out of the home by wind) and ventilation (a mechanical form of

7 infiltration). Since the home was built before ventilation systems were installed in residential homes, this will also be excluded from the model. Calculating Heat Loss To calculate the design heat load, the heat loss per C must be determined. Equation shows the general equation that will be used for this model (Q TOTAL ). QTOTAL is the total heat loss from the home. Q Q TOTAL SKINLOSS = Q Q = wall area windowarea door area ceiling area crawlspace area slab perimeter Wall T. R. Window T. R. door T. R. ceiling T. R. crawlspace T. R. concrete factor = m C / W m = 8 W = C SKINLOSS SKINLOSS n i= 1 + Q + Q Ui Ai T K 19.54m + 1 INFILTRATION INFILTRATION 8.7m Q VENTILATION 78.78m m 1.89m m m C / W (Eq 3.1.1) The total loss through the house envelope (Q SKIN LOSS ) can be calculated using Equation Each portion of the home is analyzed and the heat loss through each portion is summed together to get the total heat loss through the home. The constant K is used to convert the imperial R-value of thermal resistance to metric units. Entering the values for each portion of the home gives a base heat loss of W/ C. (Eq 3.1.) Once the design heat load is known, the number of air changes must be determined so the heat loss due to infiltration can be calculated. Equation shows how to calculate the number of air changes per hour based on the effective air leakage on the house. The effective air leakage can be measured using a blower door test. This involves placing a fan in a door, sealing the opening and evacuating the air from the home. A sensor on the fan determines the amount of airflow needed to maintain a certain air pressure in the home. From this, the effective air leakage can be determined. Since a blower door test requires specialized equipment, it could not be conducted on the project home. The effective heat loss was taken from a similar home in a similar climate [1]. The air leakage from the similar home was 1,464 cm. Since the sample house floor space was 158 m and the test house floor space was only 10 m, the air leakage was reduce to 1110 cm. This was done assuming the relationship between effective air leakages is approximately linear when comparing homes built in the same manour, geographic location and time period. Once the effective air leakage is found, the average number of air changes can be determined using Equation This equation relates the home s stack coefficient (based on the number of stories), design temperature differential, wind-screening coefficient (based on wind shielding around the home), the average wind speed, and the volume of the home. The stack coefficient for a one-story building is (m 3 /hr cm ) / C [] and the wind coefficient for a one-story home with moderate shielding is (m 3 /hr cm ) / (m/s) []. The temperature differential is the same as when determining the design heat load, 5 C. The volume of the home is m 3. This gives an average of 0.87 air changes per hour. For comparison, a building is only considered unusually tight if the number of air changes per hour due to infiltration is less than 0.35 [3]. 3

8 A CPH = A = A L CPH C T + C S = V HOUSE 1110cm = 0.87air changes per hour W v W ( m / hr cm ) ( m / hr cm ) C 5 C m ( m / s) (Eq 3.1.3) (.60m / s) Once the number of air changes per hour is known, the heat lost per degree Celsius due to infiltration can be determined. Equation finds the amount of air that is heated in one hour and multiplies that by the amount of heat needed to raise 1m 3 of air by 1 C. Using the numbers calculated in previous equations, the heat loss per degree Celsius due to infiltration is calculated to be 99.9 W/(hr C). Q INFILTRATION = A = E V CPH cm HOUSE W m 3 hr m C kw 5 C = 99.9 hr C (Eq 3.1.4) To get the design heat load, the design temperature must be known. It can be obtained from data provided by NASA [4]. The upper temperature is set to 18 C (to stay consistent with further Heat Degree Day calculations) and the design heating temperature is -7 C (from the data on NASA s website). This gives a temperature differential of 5 C. The total heat loss per degree Celsius is W. This gives a design heat load of 9.411kW. This value will be used to determine size of the new proposed heating system. Heating Degree Days A common way to compare the heat loads of different homes is to use the Heat Degree Day method. This is a way of estimating how much energy is used to heat a home during the heating season. Through many experiments, it has been determined that most homes start heating when the outside temperature drops below 18 C [5]. To get the heating degree-day count for a particular day, subtract 18 from the mean daily temperature. If the mean temperature is above 18 C, then there was theoretically no heating for that day. The method is not 100% accurate, but it gives an easy way to compare homes without expensive monitoring systems. To estimate the heating load over the heating season you need to know the number of Heating Degree Days. This information can be found at the Canadian Weather Office [6]. Download the daily averages for the heating period (October 1 to April 30 in Sidney, BC) and total up the numbers in the HDD 18 column. Then use Equation to estimate the amount of energy needed over the heating season. Q HDD18 4hr W = HDD18( C day) QLOSS day C 4hr W = 309 C day = 0.86MWh day C (Eq ) To estimate the amount of Natural Gas needed for the heating season, divide the estimated seasonal energy consumption by , which is the energy content of natural gas per cubic metre (i.e. MWh/m 3 ). From the data collected from the homeowners the estimated heating energy and natural gas consumption are. times higher than the actual heating energy and natural gas consumption for that period. This shows that the estimated seasonal energy consumption should only be used as an estimate. The main purpose of Heating Degree Days is to compare the effectiveness of changes made to the home (i.e. insulation upgrades, turning down the thermostat at night, upgrade efficiency of the furnace, etc). 3 4

9 Since the temperature of the heating season is never the same each year, this method gives a way of comparing two seasons. If the number of Heating Degree Days in the heating season decreases by 10%, the seasonal energy consumption should decrease by 10%. If the Heating Degree Days are constant between two seasons and the house insulation was upgraded before the second heating season, the homeowner should see a decrease in heating consumption Recommendations The recommendations made here are as a result of calculation similar to those in Section They were also made using the client software outlined in Section 3.4. Option 1 If the homeowner was to hire a contractor to remove the drywall, reinsulated with polyurethane to R-4, install new vapour barrier, install new drywall, mud, sand and paint the walls, install R-40 fiberglass insulation in the ceiling and reduce the infiltration by 50%, the project would cost around $14,000. The annual energy savings would be $170 per year. It would save approximately t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) is % per year, it would take 49 years to see positive returns on the renovations. Option If the homeowner was to hire a contractor to insulate the walls to R-14 (drill holes in the wall and blow cellulose into the walls), increase the ceiling insulation to R40 (fiberglass bats) and reduce the infiltration by 5% (weather-stripping doors and moving windows as well as using expanding foam to fill gaps in around window and door frames), the project cost $300. The annual energy savings would be $110 per year. It would save approximately 0.9 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) is % per year it would take 3 years to see positive returns on the renovations. Option 3 If the homeowner was to do the project themselves the savings wouldn t be as high, but the return would be much sooner. If the homeowner was to insulate the ceiling to R-40, calk and weather -strip doors and windows to reduce the infiltration by 5%, the project would cost $1,000. The annual energy savings would be $85 per year. It would save approximately 0.19 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 1.5 years to see positive returns on the renovations. Option 4 If the homeowner was to hire a contractor to install new thermal windows (vinyl frame, double pain, argon gas between pains) with a R-4.3 rating, the project would cost $400. The annual energy savings would be $85 per year. It would save approximately 0. t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 34.5 years to see positive returns on the renovations. Option 5 If to renovations detailed in Option 1 and Option 4 were made to the home, the project would cost $18,00. The annual savings would be $50 per year. It would save approximately 0.64 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 45 years to see positive returns on the renovations. Because these recommendations are being made to homeowners and not business executives it is a highly subjective decision. Some homeowners will decide that the cost is justified by the reduction in their GHG emissions, while others will only be focused on the initial cost. For this reason, I am only presenting the options and not making decisions for the homeowner. 5

10 3. Alternative Energy Feasibility Studies The main purpose of this study was to show homeowners that alternative energy systems are not purely science fiction or for the elite and eccentric. For each of the alternative energies listed below a brief explanation of the analysis model will be provided with the exception of wind energy Common Analysis Components There are several features that are common to many of the studies that will be addressed here. They include issues such as solar insolation, environmental conditions and heating loads. The environmental conditions and heating loads were covered in Section 3.1 so this section will concentrate on solar insolation. The first step in designing a solar system is to establish the conditions that the system will be installed into. This involves average weather conditions and house orientation. To get the monthly solar insolation for Victoria, data was retrieved from the Environment Canada s website [6] as well as, a website setup by NASA specifically for RETScreen users [4]. Setting the Solar Collector Azimuth Angle There are two angles that are critical to the operation of the solar collector system. The first is the azimuth angle or the number of degrees that the collector is moved away from true South. Thanks to the foresight of the original contractor, the front of the house faces true South, as well as, the majority of the roof. This enables solar collectors to be mounted directly to the roof without any azimuth corrections. In this case any change to the azimuth angle would reduce the yearly solar insolation in the plane of the solar collector. To show the effect of azimuth changes, Figure 3..1 and Figure 3.. have been included. Figure 3..1 shows the average daily insolation while Figure 3.. shows the yearly insolation totals. The values in both figures are the amount of solar insolation in the plane of the solar collector. Both figures were created using data generated by the RETScreen Solar Water Heating Project Model [7]. 7.0 Average Daily Inslation Received by the Solar Collector Collector Tilt is 8 Degrees 6.0 Jan Average Daily Insolation (kwh/m²/day) Feb Mar Apr May June July Aug Sept Oct Nov Dec Azimuth (Degrees West from Due South) Figure 3..1 Average Daily Insolation While Varying Collector Azimuth 6

11 Average Daily Inslation Received by the Solar Collector Collector Tilt is 8 Degrees Yearly Insolation (kwh/m²/year). 1,400 1,350 1,300 1,50 1, Setting the Solar Collector Tilt Angle Azimuth (Degrees West from Due South) Figure 3.. Yearly Insolation While Varying Collector Azimuth The second critical design angle is the tilt angle or the number of degrees that the collector is moved from the horizon. The tilt angle has a large effect on how much solar insolation is absorbed by a solar collector. Figure 3..3 illustrates the effect of collector tilt and gives the amount of solar insolation in the plane of the solar collector. The values shown in Figure 3..4 are yearly totals of solar insolation in the plane of the solar collector. Both figures were created using data generated by the RETScreen Solar Water Heating Project Model. 7.0 Average Daily Inslation in the Plane of the Solar Collector Collector Azimuth is 0 Degrees (True South) Average Daily Insolation (kwh/m²/day) Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Solar Collector Tilt ( from Horizon) Figure 3..3 Average Daily Insolation While Varying Collector Tilt 7

12 1,450 Average Daily Inslation in the Plane of the Solar Collector Collector Azimuth is 0 Degrees (True South) Yearly Insolation (kwh/m²/year) 1,400 1,350 1,300 1,50 1,00 1,150 1,100 1,050 1, Solar Collector Tilt ( from Horizon) Figure 3..4 Yearly Insolation While Varying Collector Tilt For an off-grid installation the system is designed around the month with the lowest monthly insolation. In the northern hemisphere this is generally the month of December. Since existing residential systems are already tied to the public utility grid it is not cost effective to completely remove it. For this reason, the optimal tilt angle for yearly insolation will be determined instead of the optimal tilt for December s insolation. To determine the optimal tilt angle for the solar collectors the data shown in Figure 3..3 was used to create yearly insolation totals. These totals are shown in Figure From this plot a third order polynomial can be generated to represent the data set. The equation generated using Microsoft Excel is shown in Equation Its first derivative can be seen in Equation f(x) = E 4x x x (Eq. 3..1) f (x) = 6E 4x x (Eq. 3..) If Equation 3.. is set to zero the optimal tilt angle is from the horizon. In order to save some construction cost and roof reinforcement design the option of mounting the solar collector directly to the angle of the roof is also considered. If the solar collector were mounted at 8, the yearly insolation would be kwh/m²/year. This represents a 0.67% drop in yearly insol ation when compared to the optimal angle of 34. Since the costs of creating a stand for the solar collector would out weigh the losses from dropping collector to sit flat against the roof the design angle will be set to 8. For comparison, if the collector tilt angle were set to 69 to optimize December s collector performance, the yearly insolation would be reduced by 14.6% (or 5.8 kwh/m²/year) from the optimal case. This reduction in performance would only increase December s performance by 0.09 kwh/m²/month. 3.. Solar Heated Domestic Hot Water Solar heated domestic hot water is one of the two most cost effective alternative energies. The following explanation is meant to accompany the study attached in Appendix A. Design decisions will also be identified. The energy study was conducted using the RETScreen Solar Water Heating Project Model. Glazed collectors were chosen for this project because of the three different options (unglazed, glazed and evacuated) they provide better efficiency than the unglazed and lower cost than the evacuated 8

13 systems. If this were an off-grid project, a more efficient system may become cost efficient, but for ongrid projects glazed will do the job. The actual solar collector chosen was the Swiss Solar Tech MULTISOL M40. This company was chosen because they are located in BC so product support will be more accessible and they are more familiar with BC climates. Since the winters in Victoria can reach below freezing, a closed system is required. This is unfortunate because an open system is more cost effective and doesn t require a heat exchanger. A tank size equal to the daily hot water requirements was chosen to reduce the effect of cloudy days on the system. In order to get a solar fraction of 50% or more an array size of 3 solar collectors was chosen. The rest of the model is cost analysis, Green House Gas emission reduction and financial analysis. Since there are no decisions to make on these pages they will just be summarized. The initial costs will be $4,000, the annual costs will be $5 for the circulating pump power, and the annual savings will be $60. The annual Green House Emission reduction will be the equivalent of 1.06 t CO/yr (includes CO, CH 4 and N O emissions). The simple payback period is 15.7 years, but if the energy cost escalation rate is % per year, the time to positive returns will be 14.6 years. The system will provide 59% of the home s domestic hot water requirements. The solar collectors are estimated to deliver 3MWh to the domestic hot water system over one year at an efficiency of 36%. 3.. Wind Power Unfortunately, electricity generated by wind energy does not extend itself to residential applications, especially in BC. But this does not mean that wind energy cannot still be used. Wind assisted ventilators can be installed on the roof to lower attic temperatures in the cooling season as well as ventilate moist air trapped in the attic. The volume of air enclosed by the attic is approximately 65m 3. A wind-assisted ventilator (or Whirlybird) that can move 9.86m 3 per minute with a constant wind of 8 KPH will create a complete air change every 7 minutes. Since this home only has two louver vents on each end of the home it is recommended to increase the attic ventilation. During the testing period temperatures reached about 37 C in the attic while the maximum -recorded outdoor temperature was only 7 C. This indicates that there is not adequate ventilation. This could also cause problems in the winter with condensation leading to mold and mildew growth Generating Electricity with Photovoltaic Cells Generating electricity with photovoltaic cells is a very clean source of energy, but as the analysis will show, it is only cost effective over very long periods. The following explanation is meant to accompany the study attached in Appendix B. Design decisions will also be identified. The energy study was conducted using the RETScreen Photovoltaic Project Model. The biggest design decision with photovoltaic systems is whether or not to have an on -grid or off-grid system. The greatest advantage of an off-grid system the home is no longer susceptible to power disruptions. The greatest disadvantage is that the costs are enormous and often the investment never receives positive returns. Since this is a residential installation only the on -grid system will be considered. The tilt and azimuth angles were determined in section 3..1 to be 8 and 0 respectively. Another major design with photovoltaic systems is the tracking system. There are 4 main options: fixed (no tracking), one -axis tracking, two-axis tracking and azimuth tracking. While fixed produces the least amount of power out of the four options, it is the least expensive and requires no annual maintenance. The other systems require expensive tracking systems and are not typically installed on a residential roof. 9

14 Since the cost of a system is nearly proportional to the collector output, the size of the system was chosen to be 33% (4MWh) of the annual consumption. Canadian Solar made the chosen solar collectors. They were chosen because they are a Canadian supplier and there will be no import fees and fewer support issues. The panels have an efficiency of 17.6% and have a maximum power rating of 190 W. To get 4MHw of power (annually), 18 panels are needed which give an array size of 19.4 m with an output of 3.4 kw PEAK. The DC to AC inverter rating was chosen to be just under the peak rating of the collector array. This was done to keep costs down and because the array will operate at peak output for only a short period of time each day so the cost of a larger inverter isn t justified. The rest of the model is cost analysis, Green House Gas emission reduction and financial analysis. Since there are no decisions to make on these pages, they will just be summarized. The initial costs will be $7,000, there are no annual costs for a photovoltaic system, and the annual savings will be $60. The annual Green House Emission reduction will be the equivalent of 1.87 t CO/yr (includes CO, CH 4 and N O emissions). The simple payback period is years, but if the energy cost escalation rate is 5% per year, the time to positive returns will be 39.7 years. The system will provide 36% of the home s electrical needs. The solar collectors are estimated to deliver 4MWh to the electrical system over one year at an efficiency of 13.3%. The energy production cost per kwh is $ Active Solar Space Heating Space heating with active solar collectors is a very clean source of space heating. The following explanation is meant to accompany the study attached in Appendix C. Design decisions will also be identified. The energy study was conducted using the RETScreen Solar Air Heating Project Model. Active solar space heating is accomplished by covering an area of the house with material similar to black sheet metal. Natural convection causes the air behind the panels to flow up the sheet metal and towards in intake fan. The fan takes the warm air and distributes it around the home. In order to get the maximum solar gain out of the solar collectors they will be place on the roof instead of the walls. This is because of the large number of tall trees in front of the house. The heating system will also only be used during the heating season. During the cooling season the hot air will be allowed to vent away from the home. Since the duration of use has changed this allows a new tilt angle to be chosen. A similar method of choosing the tilt angle to that shown in section 3..1 will be used. Equation 3..3 gives the average daily insolation over the heating season. Equation 3..4 gives the first derivative. 3 f(x) = 1.994E 6x -1.79E 3x x (Eq. 3..1) (x) = 5.98 E 6x -3.58E 3x f (Eq. 3..) If Equation 3..4 is set to zero the optimal tilt angle is from the horizon. There are not a lot of design decisions to make with active solar heating. The system will be a residential, air ventilation system. The design objective is to provide a high temperature rise. Other options include normal operation and high air volume operation. Since the objective of this system is to heat a small area, a large airflow is not needed; so raising the temperature becomes the project objective. Since there is no current ventilation system a fan will be installed to circulate the air. To achieve the maximum insolation collection the panels will be black. The rest of the model consists of the cost analysis, Green House Gas emission reduction and financial analysis. Since there are no decisions to make on these pages, they will just be summarized. The initial costs will be $300. There are no annual costs for a photovoltaic system and the annual savings will be $110. The annual Green House Emission reduction will be the equivalent of 0.4 t CO/yr (includes CO, CH 4 and N O emissions). The simple payback period is 0.9 years, but if the energy cost escalation rate is % per year, the time to positive returns will be 17.3 years. The system will provide 5% of the home s space heating needs. The solar collectors are estimated to deliver 1.7MWh to the space heating system over one year at an efficiency of 47%. The average temperature rise during the heating season will be 10.3 C. 10

15 \ 3..5 Passive Solar Design The goal of a passive solar space heating home is to use the sun and building envelope to heat the home. This is done using specifically placed windows and a thermal storage system. Examples of thermal storage include concrete, water and stone. In a typical passive solar space heated home, the Southern side will have a large number of carefully placed windows and the floor and possibly the wall opposite to the wall will be made of concrete or stone. In some applications there are large pillars of water in front of the Southern windows to capture and store the solar energy. Northern windows should be kept to a minimum. Passive solar design is only cost effective when considered while designing the home. Retrofits can be very costly and often the upgrade costs will never be returned by the space heating savings. But in order to show how passive solar design can be integrated into a home a brief analysis of the existing home will be conducted. This analysis will show what to consider when designing the location and sizes of the Southern windows. The overhang above the window is critical in keeping the home cooler in the summer and warmer in the winter. Figure 3..5 shows the sun angles for all the Southern facing windows. In the winter when the sun is lower in the sky the sun's energy penetrates deep into the home to provide some space heating. But in the summer, when the house doesn t need space heating, the overhang blocks the sun s energy. All of the Southern windows are positioned to block the summer sun and receive the winter sun. Figure 3..6 shows sun angles through the year. Summer Sun Winter Sun Master Bedroom Summer Sun Winter Sun Summer Sun Summer Sun Winter Sun Winter Sun Living Room Main Entrance Bedroom #1 Figure 3..5 Passive Solar Analysis of Southern Windows Jun 1 18 Jul 1, May 1 1 Aug 1, Apr 1 30 Sep 1, Mar 1 41 Oct 1, Feb 1 53 Nov 1, Jan 1 61 Dec 1 Figure 3..6 Sun Angles During the Year 11 64

16 If a home owner wanted to make their home more efficient for passive heating they have the following options: the windows could be replaced to receive the sun s energy, but retain the building s heat; the flooring could be removed, reinforced and a thin layer of concrete poured over the floor to store the sun s energy in the winter; columns of water could be installed in front of the windows to store the sun s energy in the winter; and finally, thermal blankets could be placed over the windows during winter nights to further reduce heat loss through the windows Geothermal Space Heating Geothermal space heating and cooling is very clean and efficient. The following explanation is meant to accompany the study attached in Appendix D. Design decisions will also be identified. The energy study was conducted using the RETScreen Ground-Source Heat Pump Project Model. The main idea behind geothermal energy is that the earth is like a large heatsink because it s temperature changes very little from season to season. This can be used to draw heat from the earth when the surface is cold and inject heat into the earth when the surface is hot. The two main geothermal systems are horizontal and vertical closed -loop. Horizontal closed-loop requires a larger footprint than vertical closed-loop. Horizontal systems are also typically cheaper than vertical due to the method of burring the loops. Since residential lots are typically not large enough for horizontal systems a vertical system will be used. The two main design criteria for geothermal systems are cooling oriented and heating oriented. In cold climates where there is more annual heating than cooling, a heating oriented geothermal system may not be financially viable, while a small cooling oriented system would most likely be. Since Victoria is a temperate climate the system will be designed for space heating. A standard heat pump was chosen with a heating coefficient of performance of.8 and a cooling coefficient of performance of 3.5. To reduce the amount of land used for the geothermal system a compact vertical system is used. This adds a marginal increase in cost, but it ensures that it will fit in the homeowner s lot. The amount of land required is 11m. The depth of the hole desirable for the loops will be 10m in order to get the higher earth temperatures. The environmental data was provided by NASA s website, as well as the NRC s website. The heating and cooling loads were calculated in Section The design-heating load is 7.6kW and the designcooling load is 1.8 kw. The annual heating energy demand is taken from the utility bills. The annual heating energy demand is 9.74MWh with a 67% efficient furnace. This gives an annual heating demand of 6.5MWh. The cooling demand is merely an estimate. The rest of the model consists of the cost analysis, Green House Gas emission reduction and financial analysis. Since there are no decisions to make on these pages they will just be summarized. The initial costs will be $8,00 the annual costs are $150 for electricity to run the heat pump,\ and the annual savings will be $480. The annual Green House Emission reduction will be the equivalent of 0.85 t CO/yr (includes CO, CH4 and NO emissions). The simple payback period is 5.5 years, but if the energy cost escalation rate is % per year, the time to positive returns will be 0.4 years. The system will provide 100% of the home s space heating and cooling needs. The seasonal heating coefficient of performance is 3.1 and the seasonal cooling coefficient of performance is Other Options There are other options available to the homeowner beside envelope upgrades and adopting alternative energies. These options include upgrading the domestic hot water heater, upgrading the space-heating furnace, changing fuels for the domestic hot water or space-heating furnace, reducing water 1

17 consumption, and installing a programmable thermostat. This section gives an overview of the results of each option Upgrading Appliances The benefits of upgrading the furnace efficiency are very simple to calculate. The reduction in energy costs is only an estimate, but it is close enough to be used in this model. All energy transfer systems have their inefficiencies. The efficiencies listed on the appliance are also relative efficiencies. Engineers determined the optimal heating cycle for the given application and made that equal to 100%. The appliances are then judged on this new marking point. From the homeowner s utility bills we can determine that actual season heat load of the home. The efficiency listed on the heating appliance is used as the base case. The new appliance is used as the upgrade case. Since cost is directly related to the amount of fuel used we will use cost as the upgrade indicator. Equation shows how to calculate the savings that an upgrade will allow. Savings = ( eff eff ) NEW eff NEW BASE (Eq ) Upgrading a Natural Gas Space Heating Furnace Using Equation with a base efficiency of 65%, an upgrade efficiency of 93% and an annual energy cost of $460 the annual savings would be $140. The project would cost $1,900. It would save approximately 0.36 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 1 years to see positive returns on the upgrade. Upgrading a Natural Gas Domestic Hot Water Heater Using Equation with a base efficiency of 57%, an upgrade efficiency of 93% and an annual energy cost of $390 the annual savings would be $150. The project would cost $1,700. It would save approximately 0.80 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 10.3 years to see positive returns on the upgrade Changing Heating Fuels Annual Cost The benefits of changing the fuel to heat your home or hot water are very simple to calculate. The reduction in energy costs is only an estimate, but it is close enough to be used in this model. Each type of fuel has its specific heat quantity. If the heat quantity is known then a comparison can be made. The annual heat load can be calculated using Equation This is the amount of energy that the house would use if the appliance were running at 100% efficiency. Equation shows how to calculate annual costs if the appliance was changed from Natural Gas to electricity. GJ $ Annual Heat Load = Appliance Efficiency 3 3 m m $ / kwh Annual Heat Load CostsELEC = GJ / kwh Appliance Efficiency 1 Annual Cost (Eq. 3.3.) (Eq ) 13

18 Changing Hot Water Tank From Natural Gas to Electric Using Equation 3.3. and Equation we can find the annual domestic hot water heating load and the annual cost if the hot wat er tank was run on electricity. GJ $0.496 Annual Heat Load = m m = 17.03GJ Costs ELEC $ GJ = GJ kwh = $ $390 This equation shows that at the same efficiency heating with Natural Gas is less expensive than heating with electricity. Since 57% is very low for an electrical hot water heater, Equation is used to find the annual cost of a 93% efficient hot water heater. Using Equation with a base efficiency of 57%, an upgrade efficiency of 93% and an annual energy cost of $390 the annual savings would be $60. The cost to upgrade to an electrical hot water heater would be $, It would save approximately 0.31 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 7.78 years to see positive returns on the upgrade. Changing Furnace From Natural Gas to Electric Using Equation 3.3. and Equation we can find the annual domestic hot water heating load and the annual cost if the hot water tank was run on electricity. GJ $0.496 Annual Heat Load = m m =.91GJ Costs ELEC $ GJ = GJ kwh = $ $460 This equation shows that at the same efficiency heating with Natural Gas is less expensive than heating with electricity. Since 65% is very low for an electrical hot water heater Equation is used to find the annual cost of a 93% efficient furnace heater. Using Equation with a base efficiency of 65%, an upgrade efficiency of 93% and an annual energy cost of $460 the annual savings would be $13. The cost to upgrade to an electrical hot water heater would be $, It would save approximately 0.11 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 71 years to see positive returns on the upgrade Reducing Water Usage One of Canada s abundant natural resources is clean drinking water. Since our reserves are so high it is very inexpensive ($1/m 3 or $0.001/L). In some areas a general utility fee pays for water, but in Victoria, water is metered and residents pay according to what they use. The other cost associated with water is the domestic hot water costs. The average water consumption was 560L per day. With the utility costs and the costs for domestic hot water each litre of cold water cost $0.001 and each litre of hot water cost $ The usage rates per day for different areas of the home can be found in Figure Also included in Figure are the daily and yearly totals and respective costs. 14

19 Area Flow Rate Usage Hot Water Cold Water Cost Dishwasher Once per day 40L 0L $0.5 Clothes Washer Weekly avg / 7 10L 40L $0.10 Shower 10.4L / Min 3 x 7 min each 109L 109L $0.75 Faucets 7.5L / Min 14 minutes per day 5L 5L $0.38 Toilets 1L / Flush 14 flushes per day 0L 168L $0.17 Daily Total 11L 369L $1.64 Annual Total 79,300L 134,900L $614 Option 1 FIGURE HOT AND COLD WATER USAGE WITH COSTS The shower time is reduced by 1 minute per shower and the toilet s flow rate is reduced by L/ flush (water proof container filled with sand and placed in the tank). This would be a free upgrade an d it would save $50 each year. It would save 71,576L of hot water, 119,07L of cold water and approximately 0.30 tco/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) is % per year the savings per year would be $50(1.0) N using N as the number of years after the upgrade was done (i.e. the first 3 years would save $51, $5 and $53 each year respectively). Option The shower time is reduced by 1 minute per shower and the toilet s flow rate is reduc ed by L/ flush (water proof container filled with sand and placed in the tank), a low-flow shower head is installed to reduce the flow rate by 1L/min, and low-flow aerators are installed on the faucets to reduce the flow rate by 1L/min. The cost of this project would be $50. The annual savings would be $93 per year. It would save 11,530L of hot water, 1,750L of cold water and approximately 0.84 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 0.54 years to see positive returns on the upgrade Programmable Thermostat In order to determine the effect of lowering the temperature of the home when a comfortable temperature is not needed (sleeping and during work) data from the Canadian Weather Office was analyzed. Two calculations were made on hourly mean temperatures recorded during the heating season. The first step was to record the number of Heating Degree Hours. This is done by finding the difference between the hourly average temperatures and 18 C (unless the temperature was above 18 C). The sum of all the differences for the day equals the Heating Degree Hours. The second was to record the number of Heating Degree Hours with a temperature setback. The times where the temperature was set back were 1:00AM to 5:59AM, 9:00AM to 3:59PM, and 11:00PM to 11:59PM. During these times, the difference between 18 C setback and the temperature were recorded (i.e. HDH = 18-setback-temperature). During the other hours, the HDH was the difference between 18 C and the temperature. The two total were then compared to find the savings of the setback method. Option 1 A programmable thermostat will be installed and the home s internal temperature will be set back by 3 C (19 C) for the following timer periods 1:00AM to 5:59AM, 9:00AM to 3:59PM, and 11:00PM to 11:59PM and C for the rest of the time. The cost of this project will be $45. The annual savings will be $57 per year. It will save approximately 0.50 t co/y r of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it would take 0.84 years to see positive returns on the upgrade. 15

20 Option A programmable thermostat will be installed and the home s internal temperature will be set back by 3 C (0 C) for the following timer periods 1:00AM to 5:59AM, 9:00AM to 3:59PM, and 11:00PM to 11:59PM and 3 C for the rest of the time. The cost of this project will be $45. The annual savings will be $4 per year. It will save approximately 0.1 t co/yr of GHG emissions per year. If the energy cost escalation rate (rate on energy cost increase per year) were % per year it will take 1.98 years to see positive returns on the upgrade. 3.4 Software Analysis Report A software package is provided to the homeowner after the analysis is complete. It contains all the data that the analysis package can provide, but in an easy to use and customize fashion. The next sections outline why it is provided, what services it can provide, and how it works Why it Provide a Software Analysis As evident from the limited number of options outlined in the previous sections a nearly endless number of variations are possible when upgrading a home and integrating alternative energies. In order to allow the homeowner to explore each combination without conducting a large number of calculations, a software package was created. This software package performs all the calculations needed What the Software Analysis does This section outlines the abilities of the software package given to clients after the home analysis has been completed. The Insulation Panel allows the client to customize the upgrades they wish to make to their home. For example, if the homeowner wishes to upgrade the doors only, they can see how much of an impact this will have on their heating costs. It also serves as an educational tool to show users which components have the largest impact, at what point further upgrades of a component no longer have the same dramatic impact and which improvements provide the best return on investment. The Solar Hot Water Panel, the Solar Space Heating Panel and the Photovoltaic System Panel all give a rough estimate of the cost of each system as the size increases. Each size has it s own set of physical system parameters, performance system parameters and cost analysis. This enables the homeowner to understand how the system becomes more efficient, cost effective, and environmentally friendly as the size varies. The Other Options Panel gives a few low cost options along with the savings they will create. It confirms the idea that reducing water consumption and setting back the thermostat does have a significant effect on utility costs. It shows the effect of furnace and hot water heater efficiency on the cost of utilities as well as the choice in fuel How the Software Analysis Works The software itself is an event driven program so it requires very little system resources to run. It will run on any Windows base operating system from Windows 98 to Windows XP. After each adjustment to the model the affected variables are calculated. This removes the need for the user to click update after each change. The program was designed to provide the maximum amount of flexibility while still maintaining a simple layout and user-friendly interface. Due to the large number of calculations needed to perform a home energy analysis and alternative energy analysis some of the panels only use look up tables. This is done for all the panels with the exception of the Insulation Panel. There are nearly 0,000 combinations on the Insulation Panel alone. Because the calculation is not difficult and the permutations are so high it was decided to perform the 16