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All Subjects: Solar Power
Creators: Phelan, Patrick
Member of: Theses and Dissertations

Experimental demonstration of photovoltaic powered solar cooling with ice storage

Description

The ability to shift the photovoltaic (PV) power curve and make the energy accessible during peak hours can be accomplished through pairing solar PV with energy storage technologies. A prototype hybrid air conditioning system (HACS), built under supervision of project head Patrick Phelan, consists of PV modules running a DC compressor that operates a conventional HVAC system paired with a second evaporator submerged within a thermal storage tank. The thermal storage is a 0.284m3 or 75 gallon freezer filled with Cryogel balls, submerged in a weak glycol solution. It is paired with its own separate air handler, circulating the glycol solution. The refrigerant flow is controlled by solenoid valves that are electrically connected to a high and low temperature thermostat. During daylight hours, the PV modules run the DC compressor. The refrigerant flow is directed to the conventional HVAC air handler when cooling is needed. Once the desired room temperature is met, refrigerant flow is diverted to the thermal storage, storing excess PV power. During peak energy demand hours, the system uses only small amounts of grid power to pump the glycol solution through the air handler (note the compressor is off), allowing for money and energy savings. The conventional HVAC unit can be scaled down, since during times of large cooling demands the glycol air handler can be operated in parallel with the conventional HVAC unit. Four major test scenarios were drawn up in order to fully comprehend the performance characteristics of the HACS. Upon initial running of the system, ice was produced and the thermal storage was charged. A simple test run consisting of discharging the thermal storage, initially ~¼ frozen, was performed. The glycol air handler ran for 6 hours and the initial cooling power was 4.5 kW. This initial test was significant, since greater than 3.5 kW of cooling power was produced for 3 hours, thus demonstrating the concept of energy storage and recovery.

ContributorsPeyton-Levine, Tobin (Author) / Phelan, Patrick (Thesis advisor) / Trimble, Steve (Committee member) / Wang, Robert (Committee member) / Arizona State University (Publisher)

Created2012

A Bench-Top Demonstration of a Novel Material Thermal Storage System Test Apparatus

Description

As part of a United States-Australian Solar Energy Collaboration on a Micro Urban Solar Integrated Concentrator project, the purpose of the research was to design and build a bench-top apparatus of a solar power concentrator thermal storage unit. This prototype would serve to be a test apparatus for testing multiple thermal storage mediums and heat transfer fluids for verification and optimization of the larger system. The initial temperature range for the system to test a wide variety of thermal storage mediums was 100°C to 400°C. As for the thermal storage volume it was decided that the team would need to test volumes of about 100 mL. These design parameters later changed to a smaller range for the initial prototype apparatus. This temperature range was decided to be 210°C to 240°C using tin as a phase change material (PCM). It was also decided a low temperature (<100°C) test using paraffin as the PCM would be beneficial for troubleshooting purposes.

ContributorsLee, William John (Author) / Phelan, Patrick (Thesis director) / Wang, Robert (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of International Letters and Cultures (Contributor)

Created2015-05

Solar Power and Controllable Light Transmission for Greenhouses

Description

Increasing reliable produce farming and clean energy generation in the southwestern United States will be important for increasing the food supply for a growing population and reducing reliance on fossil fuels to generate energy. Combining greenhouses with photovoltaic (PV) films can allow both food and electric power to be produced simultaneously. This study tests if the combination of semi-transparent PV films and a transmission control layer can generate energy and spectrally control the transmission of light into a greenhouse. Testing the layer combinations in a variety of real-world conditions, it was shown that light can be spectrally controlled in a greenhouse. The transmission was overall able to be controlled by an average of 11.8% across the spectrum of sunlight, with each semi-transparent PV film able to spectrally select transmission of light in both the visible and near-infrared light wavelength. The combination of layers was also able to generate energy at an average efficiency of 8.71% across all panels and testing conditions. The most efficient PV film was the blue dyed, at 9.12%. This study also suggests additional improvements for this project, including the removal of the red PV film due to inefficiencies in spectral selection and additional tests with new materials to optimize plant growth and energy generation in a variety of light conditions.

ContributorsGunderson, Evan (Author) / Phelan, Patrick (Thesis director) / Villalobos, Rene (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)

Created2021-05