The Engineering Challenge stipulated that students design a refrigeration unit with a holding volume of 1 square foot that could transport small essential cargo, such as food or medicine. The temperature inside the box must be maintained at 25°F without an external power supply and the device must be able to be assembled anywhere in the world.
The first place Applied Engineering Challenge winners are Brian Kaufman, Nick Leeburg, Tony Lin, and Micah Reich of San Jose University, Calif. Their faculty advisor is Nicole Okamoto, Ph.D.
The team chose a simple wooden frame for their freezer unit due to the simplicity of fabrication and availability of the material. As refrigerant, HFC-134a was used for its less detrimental impact to the environment compared to chloroflurocarbons (CFCs). The freezer uses a swing motor compressor which allows the device to work while in transit, making the freezer more durable and able to handle vibration and changes in orientation. At 65 pounds, the freezer can readily be carried between two people.
Also critical to the freezer’s design is the solar panel and self-adjustable rack that allows a user to gather the maximum amount of sunlight. The solar panel powers an absorbed glass mat battery, which was chosen for its reliable track record in the solar industry and relative lower cost in relation to cycling life. The battery requires little maintenance and provides increased safety to the user — safety such as drop protection and no spilling of acid if broken.
ASHRAE also announced the winners of its 2013 Student Design Competition, which recognizes outstanding student design projects, encourages undergraduate students to become involved in the profession, promotes teamwork, and gives students the opportunity to apply their knowledge of practical design.
This year’s competition featured a mock design of a high-rise residential building, with retail space on the lower floors, in Dallas.
Among the 41 entries from eight different countries, three were awarded first place in the three categories that the competition offers.
First place in HVAC Design Calculations is awarded to Jayson Bursill, Natasha Palmer, Angela Walton and Gavin Wong of the University of British Columbia, Vancouver, British Columbia, Canada. Their faculty advisors are Nima Atabaki, Ph.D., Geoff McDonell and Steven Rogak, Ph.D.
Limited mechanical space available for large plant equipment and exhaust ducting resulted in the team selecting an air-cooled heat recovery chiller for the roof and high-efficiency condensing boilers for heating. Heat recovery was implemented via air-to-air heat pipes, which provide minimal leakage and are a passive technology, and allow for washroom exhaust recovery. Hydronic radiant panels were used for skin heating in the first floor retail space to lower the room air temperature and maintain occupant comfort.
The team used Ottawa, Ontario’s climate when considering weather conditions and found, when compared to the Standard 90.1-2010, Energy Standard for Buildings except Low-Rise Residential Buildings, baseline, the design is 8 percent more efficient given the constraints on mechanical space and terminal unit selection for the Ottawa climate.
Analysis of the cost of installing the necessary equipment for the heat recovery chiller gave a payback period of 13 years and a net present value of $3,358 over the life of the building. This is with the consideration of additional piping costs and the fuel (natural gas) savings for when the chiller waste heat production was equal or greater than the building heating load so the boiler could be turned down.
As an alternative energy conservation measure, the team chose triple-paned windows. The energy savings from adding an additional inert space between the environment and the conditioned space are undeniable. It was found that the use of moderately tinted triple-paned windows would reduce heating and cooling equipment size by 14 and 25 percent respectively.
First place in HVAC System Selection is awarded to Garrett Elder, Nathan Love and Nick Theimer of Kansas State University, Manhattan, Kan. Their faculty advisors are Fred Hasler, P.E., and Julia Keen, Ph.D., P.E., ASHRAE-Certified High-Performance Building Design Professional.
After considering several systems, the team chose a water source heat pump (WSHP) with sewage heat exchanger (SHX) for the building. A water source heat pump allows for load sharing between spaces within the building via a common water loop; it is an extra benefit that helps to improve the efficiency of the entire building’s heating and cooling system. The system also has the potential to be self-balancing due to the fact that simultaneous heating and cooling will occur during the year.
The addition of the SHX to the water loop provides conditioning to the loop prior to activating the boiler and fluid cooler. The system takes advantage of the fairly consistent effluent (i.e., wastewater) temperature range between 52° and 75°. This range allows the effluent to be used as a heat source or heat sink for the building’s central water loop. The SHX also consumes the lowest amount of energy when compared to other systems.
Ultimately, the students based their decision on the triple bottom line (TBL): profit, people, and planet. Though the WSHP with SHX has a higher initial cost (profit) than other suggested alternatives, the cost did not prove to be a deterrent when the students considered the many other requirements for the systems, such as low impact on energy and water usage and strict acoustic criteria. For the second factor, people, the team found that the innovative SHX allows the building and its owner to ultimately be an example and leader for sustainable energy in its region. Finally, when considering planet, the students explain how the system affects the environment: “the fact that the SHX can provide the required capacity acting as a heat sink or heat source from a renewable energy source sets this system apart.”
First place in Integrated Sustainable Building Design is awarded to Jiayi Qiu, Dalin Si, Yukai Wu, Zhongzhe Wu, Ruijun Zhang, Zhiang Zhang and Xuyang Zhong of the University of Nottingham, Ningbo, China. Their advisor is Ed Cooper.
The students redesigned the building and relocated it to Ningbo, China, on a greenfield close to basic services as stipulated by Standard 189.1, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings. They considered passive cooling strategies such as shading in summer and natural ventilation in May, June, and September. The students also explained that increasing solar heat gain and use of high thermal mass material will also contribute to thermal comfort in winter time.
For shading on residential areas, the students suggested photovoltaic devices and a double-skin façade. The façade would have one panel each and generate 22,468 kWh/year. Similar panels on the retail portion of the building would generate 7,270 kWh/year.
A closed vertical loop system was selected for the ground side circulation. Due to the space restriction, the W-type of buried pipe was chosen to increase the area of heat exchanger with ground soil in per borehole, with 240 boreholes in total.
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Publication date: 9/16/2013