This month we have begun setting up the UTest House. The UTest House is a 1300 square feet manufactured home at the University of Texas’s Pickle Research Campus. This test house is equipped with materials needed to monitor power use (W) and energy consumption (kWh), and understand how varying amounts of refrigerant in the HVAC unit, and air flow restrictions of the condenser HVAC unit change the performance of the system.
X10s are plugged into outlets, and are controlled through commands sent through electrical wiring. The X10s allow us to turn lamps and other electronics on and off through a remotely accessible computer. This allows us to control these amount of heat and moisture generated during different times of the day so that we can accurately recreate the amount of heat (sensible loads) created at different time of the day from people and other heat generating sources (e.g. appliances and electronics) . For instance, during the night, the amount of heat increases because occupants return from their jobs. Now that we understand these patterns, we are programming the test house to reflect this.
In addition to producing heat, occupants also produce moisture. To recreate this in the test house, humidifiers will beused. The amount of water evaporated was measured to determine how much moisture was released into the air. In our initial attempts, too much moisture was being released. The amount of heat and moisture we want to create is based on an algorithm, which determined the number of occupants in a home based on the number of bedroom in a home; the UTest House has three.
According to the Building Simulation Protocol by National Renewable Energy Laboratory, we should expect to see 220 Btu/person/h produced in sensible loads. Sensible Loads refers to temperature and can be detected using a typical thermometer. We should also expect to see 164 Btu/person/h in latent loads. Latent heat cannot be detected using a typical thermometer. Latent heat refers to changes in the moisture in the building, but does not result in changes in temperature.
Setting up the UTest House is in progress. Repairs to the weather station, which will measure wind speed and direction, temperature, humidity, and sunlight, will be needed before we can start testing. We will begin testing and measuring the power used by the HVAC unit shortly. Using CT collars, the current and voltage of the HVAC unit will be measured. This will be used to calculate the power required to run the unit.
Once testing is successful and complete, we will compare our experimental results with the results predicted by energy modeling software. The goal is to create an algorithm that will show if there is a fault in the HVAC system.
Update from Longhorn Lights Out! Things continue to go well with our program thanks to IBM’s support! We have now completed 6 LLO events, and continue to build on our experiences to create at great campus energy conservation program. This past month, after turning off lights on campus, we watch the documentary “Switch” by Dr Tinker, a UT Austin Faculty Member. We are also in the process of making a video about LLO to share with the world, thanks to the support from the UT Environmental Science Institute! Thank you to all the enthusiastic student volunteers who have helped out so far – we look forward to one last event before the end of the semester! We also look forward to presenting about our progress at the Engineers for a Sustainable World national conference this Saturday! We hope other universities will develop similar programs of their own!
Below is a recent article a UT Student, Elizabeth Robinson, wrote about our March event. Enjoy!
Longhorn Lights Out encourages community to conserve energy
On Friday, March 28, students, faculty and staff are encouraged to turn off light switches, computer monitors and other electronics as part of Longhorn Lights Out. The monthly event aims to raise awareness of energy conservation on campus and in the community.
Longhorn Lights Out’s latest event on Feb. 28, garnered volunteers who turned off lights in 28 buildings on campus, including 363 lights, 15 projectors and 189 computer monitors. This yielded a 14 percent energy reduction to each building visited.
During each event, organized by the UT Energy and Water Conservation Program (EWC), groups of two to five students visit up to four buildings together to turn of lights and electronics.
Past events have drawn as many as 50 volunteers who turned off 631 light switches, 49 projectors and 266 computer monitors in 35 buildings. In Fall 2013, EWC increased the frequency of the event to once every two months. In November, the University of Texas showed its support for the event by turning the Main Tower’s lights off for a night.
“As an iconic symbol of UT, we are so grateful and encouraged by UT’s support of this event,” said Kristen Cetin, a civil engineering graduate student.
EWC organized the first LLO in the spring 2013 semester. Staff, faculty and students were asked to turn off their lights and electronics. The event accomplished a 2.9 percent reduction of energy.
“This was very encouraging, but student involvement had been minimal,” Cetin said.
Since its first event, EWC has been able to partner with other student groups, including Engineers for a Sustainable World (ESW), the Campus Environmental Center and ASHRAE (The American Society of Heating, Refrigerating and Air Conditioning Engineers). Longhorn Lights Out was held twice during the Fall 2013 semester. Now, the event is held monthly, on the last Friday of each month.
“Eventually we hope to expand [Longhorn Lights Out] to the wider community and hope to get schools and the general public involved or allow them to participate in LLO events in their own homes,” Cetin said.
With the support of the university and increasing participation from students, Longhorn Lights Out continues to work to achieve whole-campus participation.
“In the ideal situation, the number of light switches and electronics we turn out each time we do Longhorn Lights Out should be close to zero,” Cetin said. “Then we know that everyone is participating.”
The University of Texas at Austin, through partnership between the UT Energy & Water Conservation Program, Engineers for a Sustainable World, and ASHRAE , have developed an energy conservation program called Longhorn Lights Out. This program’s purpose is to engage students, faculty, and staff in reducing energy use. Once a month students meet on Friday’s at 6:30 pm, and split up to survey all the campus buildings to reduce energy use by turning off lights, and electronics.
- post by Kristen Cetin
We are excited to announce that we have selected the three teams that will be advancing to the build phase of the competition! Each team submitted a detailed proposal outlining the details of their design including proof of need, expected efficiency, cost, and a construction timeline for their device. The three teams we selected and their corresponding projects are:
Team RAJ: A Peltier Thermoelectric Generator for Recreational Use
Team Gurlz: A Wind and Solar-powered Patio Umbrella
The Dream Team: Solar-powered Hydroponics
Each team will receive $300 to build a prototype of their design. They will have until May 1st to complete their builds where they will then present their designs to a panel of faculty and corporate judges. Judging criteria includes: efficiency, applicability, innovation, and creativity. We are very excited to see the results and we will provide more updates as the build phase progresses!
We are well on our way to developing an understanding of what measurable effects common faults in HVAC systems have on power (W) and energy use (kWh) of residential air conditioning units. These faults can include clogging of the outdoor unit from leaves and dust, dirty filters, refrigerant over or under charge, or other issues. By quantifying what effects these faults have, through the use of real time energy use data that a typical HEMS (Home Energy Management System) can record, we hope to develop a low-cost methodology to detect and help diagnose a fault or problem in an HVAC system before it fails or costs the home owner greater energy bills due to inefficiencies in the system.
The first step in this research is to develop models to understand what measurable variables in the energy use data are affected by these faults. This first requires the development of a baseline model that mimics how a correctly-functioning building and HVAC system work. We decided to use two models – one to focus on predicting power (W), and the other on predicting energy use (kWh). Caitlyn has been working on developing these two models.
Building Energy Model (Predicting HVAC Energy Use): The first is a building energy model that mimics the UTest House and its HVAC system at the research campus of UT Austin. Using EnergyPlus (simulation software, see Figure 1) and BEopt (Building Energy Optimization) as the interface, we used the results of the simulation models to analyze the relationship between energy use and outdoor temperature, and peak power draw and outdoor temperature. Figure 2, shows these results, comparing energy use (kWh) to outdoor temperature for each hour of the summer months (May –September) of the simulation.
HVAC Model (Predicting HVAC Power Draw): The second model is the HVAC model that mimics the behavior of the UTest House’s air conditioner. We are using a highly detailed model called ACHP (Air conditioning/ heat pump) (Figure 3). Caitlyn compiled the specs of the air conditioning unit that will be used for testing (Trane 4TTR3030A), and used them as inputs for the model. She has been working on understanding the effects of indoor and outdoor temperature on the power draw (W) of the compressor and condenser fan, and COP (coefficient of performance) (i.e. efficiency) of the system. This provides a baseline, predicted power draw and efficiency of the correctly-functioning HVAC system. Figure 4 shows an example of the variation in power and COP.
By developing these models, we will be able to understand the typical energy usage and power of an HVAC system. Having a “control” is helpful as we introducing faults to the HVAC system and see how these variables change. Caitlyn has also been working on varying flow rates of the condenser at specific outdoor temperatures to understand how a partially blocked condenser fan, one of the common faults being studied, affects power and COP.
The second step is field testing – Melissa has been spearheading this initial effort by identifying the equipment and procedures that related studies have used test the variables we need to measure in this study. She will provide more detailed updates in the next post!
Figure 1: BEOpt Energy Model of the UTest House
The interface BEopt allowed us to easily create a geometric visualization of the UTest House using physical characteristics of the building such as square footage, window areas, and orientation.
Figure 2: Energy Use (kWh) vs. Outdoor Temperature – Building Energy Modeling Results
This graph represents the relationship between outdoor temperature and energy usage. At varying indoor temperature set points, the slopes of the relationship also varies. At an indoor set point of 70°F, the rate of energy usage increases far more quickly with increase in outdoor temperature, than at an 80°F indoor set point.
Figure 3: HVAC Model
The mechanics of an HVAC system shown in this graphic are provided by the ACHP software, and include the compressor, evaporator, condenser, and expansion valve (XV).
Figure 4: Power (W) vs. Outdoor Temperature – HVAC Model Results
This graph shows the effects changes in outdoor temperature have on the predicted power draw (W) and efficiency (COP, %) of the system. With increasing outdoor temperature, power draw increases and efficiency decreases.
SmRTsolutions’ project goal is aimed at increasing the energy efficiency of residential buildings and their systems using Real Time data. We are a group of Architectural Engineering students from the University of Texas at Austin. Our team is made up of, graduate student, Kristen Cetin, undergraduate students Caitlyn Kallus, a sophomore, and Melissa Flores, a freshman. SmRTsolutions’ project goal is aimed at increasing the energy efficiency of residential buildings and their systems using Real Time data.
Spreading the Word!
This month we had the honor of presenting about LLO at the TRACS (Texas Regional Alliance for Campus Sustainability) Summit in College Station, TX on February 27th and 28th. The event attendees included approximately 150 students, faculty, and sustainability professionals from across Texas, who came together to share ideas, collaborate and improve the sustainability of higher education campuses. It was great to see so much energy and interest in sustainability programs! We are also excited that we were invited to present our efforts at the ACUHO-I/APPA Housing Facilities Conference in October, in Kansas City, Missouri. We look forward to sharing our progress and improvements, our lessons learned, as well as help other universities develop similar programs on their own campuses.
Thanks are needed! On that note, we’d also like to thank Kate Curley and Paul Ruskin from Penn State University, Nick Hennessy from Bowling Green State University, Elaine Durr from Elon University, and Jeff Severin from the University of Kansas for sharing information, ideas and suggestions about their campuses’ programs, to help us build the LLO program at UT and make it a success. We hope to do the same for other universities.
This month’s LLO: March’s Longhorn Lights Out will be on March 28th. We will meet at 6:30 pm as usual. Even if you are not a part of the UT campus, we encourage you to participate in these efforts remotely, and turn off your lights and electronics with us, and help us save energy! We’re working on developing an electronic way to allow everyone, not just UT, to participate and track your efforts. Stay tuned for more updates next month.
If you are on campus, after LLO this month we will be watching the documentary “Switch” – a great film produced under the direction of Harry Lynch and with expert guidance from Dr. Scott Tinker from UT. Below are also some pictures from the most recent LLO.
About LLO: Longhorn Lights Out was started in April 2013 by the Energy and Water Conservation Program at the University of Texas at Austin. The goal of LLO is to engage students, faculty, and staff in reducing energy use in the buildings at UT. As a part of this program, once a month LLO students meet on Friday and go to campus buildings and turn off lights, electronics, projectors and monitors that are left on in order to to reduce energy use.