Spring Investigation of Installation and Use of Energy Saving Devices in Low-Traffic Rooms. Patrick Sims Brad Pittler

Transcription

1 pring 2002 Investigation of Installation and Use of Energy aving Devices in Low-Traffic Rooms Patrick ims Brad Pittler

2 tudy and Recommendation Investigation of Installation and Use of Energy aving Devices in Low-Traffic Rooms. By: Patrick ims & Brad Pittler

3 Project ummary Introduction As per your instructions, we have investigated restroom, study room, and copy room usage across MU campus in regards to energy waste. Despite the loss of the IntelliTimer device, we were able to collect data regarding the use of these rooms and how much electricity was lost to lighting empty rooms. Method of Analysis Using both manually collected data and data based on room access records, we were able to generate a mean usage time for each type of room spread across various buildings on campus. Using this information, we came up with an average amount of electricity lost on a daily basis. The cost of electricity multiplied by this number gives us an average cost of lost electricity per day. The cost of an energy saving device was compared to this waste and forms the basis of our recommendation - assuming that all costs are fixed at the levels given throughout the project implementation plan. Findings The cost, savings, and payback time are as follows: Cost of Energy Time to olution avings Payback (years) tudy Rooms $134 (W) $ (W) $ (Lev) 1.51 (Lev) Restrooms $102 (W) $ (W) $ (Lev) 2.29 (Lev) Copy Rooms $72 (W) $ (W) $ (Lev) 1.91 (Lev) Conclusion We have found that both the solutions would pay for themselves in a relatively short period of time, and would be relatively easy to install. However, we have concerns as to the programming of these devices and the amount of energy that would be saved following this programming. This would require further study beyond the scope of this project.

4 Introduction. 1. Method of Data Collection : I i1arivai/diit6l/anecoota I Data The.Model... of the Model... 3 TheDevices... 5 Cost of Devices... 5 TheCost Breakdown... 7 Device Leviton... 7 Wàtttopper... 8 Conclusion... 8 I.

5 Introduction and Overview aving Energy through Intelligent Lighting On the recommendation of Mr. Greg Ivy at Underwood Law Library, we contacted Mr. Michael Vangelli at Campus Planning and Plant Operations to discuss how MU (and more specifically, the Law Library) could better contain energy costs. After discussion with Mr. Vangelli, we came up with a two part plan: 1) tudy room usage and lighting in restrooms, study rooms, and copy rooms around campus. This would allow us to calculate the amount of energy being wasted in a room over the space of an average day. 2) Investigate methods to reduce energy costs through cutting wasted lighting use in the aforementioned rooms through use of occupancy sensors (such as those from Watttopper.) Method of Data Collection Mr. Vangelli presented us with a device from Watttopper that would measure both the. presence of lighting and the presence of people within a room, utilizing an optical sensor to measure light levels and an infrared sensor that measured occupancy. Using this device, we could discretely take readings of a room's usage and the amount of time the. lights ran in that room. Unfortunately, Hughes-Trigg facilities group confiscated the device - despite our precautions - and proceeded to lose the device. This led us to a more novel form of data collection and analysis. Manual/Digital/Anecdotal Data Under the manual procedure we developed, the person collecting data would watch a restroom, study room, or copy room for a given period of time (usually one hour) and would record the time the room was occupied and the status of the lights in that room. Two columns were set up on a sheet of paper (or electronically) - one recording if the lights were one, another if the room was occupied. Thusly, a picture of a room's usage and the amount of electricity used could be formed. This data collection was done for each room three times - on a weekday afternoon, a weekend day, and a weekday evening - in order to develop an overall picture of room usage.

6 In cases where data did not have to be collected manually, such as where sign-out sheets or circulation data was available, we used that data to calculate room usage. In cases where the lights would always be on (i.e., the lack of a wall switch) we assumed the lights to be on during the hours a building was open. In cases where the lights could be turned off (i.e., the presence of a switch or other on/off device) we used anecdotal evidence from people familiar with the area to determine the amount of time the lights were on. Data collected for each room was used to determine a grand mean for that room (and then that building) that would be used to calculate the amount of electricity needed (or wasted) in each area. This information would be used to determine if the installation of electricity saving devices was cost-efficient, or even warranted. The average time that each type of room was used was factored into a cost minimization problem. This problem took into account room usage, lighting used, cost of electricity, and costs associated with installing an energy saving device. PA

7 Analysis and Discoveries How we came to our conclusions We had several options To calculate the estimated Annual avings with the installation of the Watttopper To calculate the time until payback (if needed) for the Wattstopper Development of the Model Our model implemented the 1) the data we gathered on percentage occupied in the type of room 2) cost of the energy per kilowatt/hour 3) the average energy used per room in kilowatts This model tells us how much money is saved by giving the average cost per room of the energy spent while being unoccupied. Annual avings Model: Pertent of Unoccupancy X Cost of Energy (kw / hour) X Energy Used per Room (kw / hour) X 16 hours X 350 days Given the following factors Cost of Energy Per Kilowatt Hour - $055 Energy Used by lights 1) 4'-32wafts 2) Incandescent bulbs watts 3

8 I Average Energy Used Calculations Restrooms: Hamon 2 x X 120 = 304 Caruth 2x16+2X32+32=128 tudy Rooms: Average Watt Usage = 216 Underwood 4 X 32 = 128 Fondren 6X120=720 Hamon 3 X X 120 = 528 Copy Rooms: Average Watt Usage = 459 Hamon 9X32=288 Caruth6X32= 192 Average Watt Usage = 240 The average amount of energy used per room (in Kw) was calculated by collecting the number of lights at the designated rooms and averaged together according to the type of room The unoccupancy percentage of the rooms was calculated by (1 - percent occupied) The savings for each type of room are as follows: tudy Rooms: (.5335 X.055 X.459 Kw X 16 X 350) = $75.42 Restrooms: (.7466X.055 X.216 KwX 16X350) $49.67 Copy Rooms: The Payback Model (.8062X.055 X.24 Kw X 16 X 350) = $59.59 Tells us how long, in years, it will take to pay off the unit before the university can actually save-money I = unit cost I annual savings 4

9 Watttopper U tudy Rooms / = 1.35 years Restrooms Copy Rooms / years / = 1.21 years Leviton (Comparable Device) tudy Rooms / years Restrooms / = 2.29 years Copy Rooms / = 1.91 years Cost of Devices Two different major players exist on the battlefield of energy efficiency devices: 1) Leviton, whose devices use a combination of infrared and ultrasonic sensors to detect occupancy, can be used in almost any area - including restrooms and other areas with barriers that would block either one or the other of the sensors used alone. 2) Watttopper, whose devices were already in use by MU. Watttopper offers several different solutions, based both on infrared and ultrasonic detection methods, depending on the type of room being surveyed. Both companies were contacted, and were given the situation and asked to provide a solution. Leviton gave us two solutions, based on room size, while Watttopper's three solutions were based on the type of room. Device Time To Install Unoccupied Cost (List Price) (Estimated) time to lights shutdown (recommended) Leviton Model 1 000WAH 60 minutes Based on pattern $ (-16 minutes) WatttopperWT-605 (for 60 minutes 16 minutes $ restrooms) WatttopperWA (for 30 minutes 18 minutes $72.00 copy rooms) WatttopperWPlR 60 minutes 15 minutes $ Table: Device Comparison 5

10 These devices appeared to be the best options available to us. Other institutions had other ways of dealing with such issues: Texas Instruments had installed infrared heat sensors in meeting rooms throughout their corporate campus. This was often found to be inconvenient as presentations in these rooms would continually be disrupted by the lights going off/coming on at unfortunate times. They chose to search for cost reductions in other areas (such as cogeneration and retiming events.) University of North Texas hired an energy consultant that studied their energy usage and installed a master control system that controlled lighting and environmental systems per their usage and efficiency requirements. This master system centrally controlled when/where lighting was used as per their studies. American Airlines Center was not using any sort of occupancy devices at the time of contact. 6

11 Putting it all Together What it means in English The cost-benefit analysis shows (based on the sample data: Installing the Watttopper solution in a restroom would cost $ and would pay for itself (disregarding inflation) in 2.7 years. The Leviton solution costs $ and it would pay itself back in 2.29 years. The Watttopper solution requires a higherpriced device in order to detect movement over rest-room stalls. The Watttopper solution in a study room would cost $ and would have a 100% return on investment in 1.35 years. The corresponding Leviton device would pay for itself in 1.51 years The Watttopper device for copy rooms would cost $72.00 and would pay for itself in 1.21 years, while the Leviton installation would pay for itself in 1.91 years. The two different solutions both have high and low points - with some of the points overlapping Leviton No choosing between devices needed for each situation - Leviton offers an allpurpose solution for all situations. Leviton's device "learns," meaning that it is unnecessary to choose the time between a room emptying and the lights going out. However, this can take up to one month to program - delaying returns. Leviton's solution is more expensive than two of the three room-solutions from Watttopper, meaning a longer time between investment and returns on investment. VA

12 Watttopper The Watttopper solution is less expensive in two of the three cases than the Leviton device, with a Watttopper representative telling us that if purchased in bulk, their list price could be reduced by 10%. The Watttopper company is familiar to MU, since the purchase of the nowmissing lntellitimer. However, the familiarity would be lost on the three different devices required to fulfill the needs of the project The Watttopper would require more study to determine the amount of delay to set on the energy-saving device. In order to facilitate comparison, we have created a chart with the Pro's and Con's of each device, with the winner in each area getting the X: Cost Criteria Leviton Watttopper Ease of procurement X X Ease of Installation Table: Possible Pros and Cons X As you can see, we have a tie. The Leviton solution would be less of a hassle to purchase, but the Watttopper representatives were more responsive and willing to work with our special needs. X Based on a target of a payback in two years, as per documents presented us, both the Leviton and Watttopper devices appear to meet the criteria. The project appears to be in the best interest of the environment and the pocketbook. However, choosing between the devices and where to install them is a difficult question. The most enticing combination appears to be installing the Watttopper wall device in copy-rooms, with the device paying for itself in under 1.25 years. There are some issues with this analysis, though: Not all of the rooms had similar traffic patterns. For instance, the Dawsón ervice Center was used almost exclusively by Physical Plant personnel. It's data was disregarded as it was considered a "special case" and had a usage rate of over 70%. The sample may not have been large enough to conclusively show the usage patterns. Though each room was sampled for at least three hours, it was in a similar time-frame, meaning that data collected during summer months or different semesters may yield different data. Data for setting up the Watttopper device was not collected, and therefore no analysis can be done as far as what setting for the device would be optimal, nor can the true energy-savings be calculated. This applies to the Leviton device as well, since we cannot be sure to what point it would choose to turn out the lights. Neither the cost of labor, nor the "hassle" effect was measured in the cost analysis. ince the employees would be salaried and paid anyway, the cost of 8

13 employee time was not taken into account. This includes any frustration felt by management in dealing with the rigors of the installation project. These limitations should be taken into account, as they are concerns that upper-level management may voice. However, despite these misgivings, we feel the project should be pushed ahead. If the Leviton solution were chosen, we would recommend a more high-level contact be made in order to obtain the best price on the devices. If the Watttopper device were chosen, we would recommend a thorough analysis of the room usage data to determine an optimal cut-off time for the devices. 9