Solar Cooling Technologies in Jordan: A Technical Study

In the recent years, solar cooling technologies for buildings have garnered increased attention. This study aimed to evaluate the performance of current solar thermal and solar photovoltaic (PV) air-conditioning technologies. Hence, the annual heating/cooling load profile and energy consumption of a reference building in the climate of Aqaba, Jordan were simulated using the TRNSYS software. The solar thermal and solar PV air-conditioning systems were designed and simulated to compensate the cooling demands. It was found that the annual cooling energy accounted for 96.3 % of the total annual energy demand (heating plus cooling) of the reference building. The solar PV and solar thermal air-conditioning systems compensated for direct cooling by 35.8 % and 30.9 %, respectively, and the corresponding compensations of cooling energy by the storage system were 7.3 % and 11.9 %, respectively. Thus, through this comparative study, we found that the storage system significantly contributed in compensating the cooling demands of the solar thermal system; however, the compensation to direct cooling was lower relative to the solar PV system

Experimental Investigation of Heat Losses from a Heat Pipe Based Parabolic Trough Collector used for Direct Steam Generation

The performance of a thermosiphon based parabolic trough collector (PTC) used for direct steam generation depends largely on the heat losses of the solar thermal system. This paper presents an experimental investigation of the heat losses in a thermosiphon based solar thermal system that used a linear receiver with a PTC for the generation of low temperature steam. A locally constructed PTC was used to concentrate sun rays to a linear copper pipe enclosed in an evacuated glass tube and held at the focal line of the PTC to heat water and generate steam. Circulation of the water in the closed-loop solar thermal system was through natural convection. A solar meter was used to measure the incident radiation flux at the experimental site and PT100 temperature sensors were installed at different points of the system to measure the temperature distribution within the system. The thermal efficiency and overall heat losses of the system were investigated by fitting the experimental data to standard equations. The results showed that the instantaneous thermal efficiency of the system was 46.48%, 43.1% and 45.32% respectively for three days examined. The overall heat losses in the system were 1211.95, 974.32 and 911.26 kwh per day respectively for the three days investigated. Heat losses from the tank accounted for over 83% of the losses for all the days examined. The evacuated glass tube reduced heat losses from the receiver to very low values of 2.31, 1.63 and 1.43 KWh per day respectively for the three days tested. The use of a better insulating material on the tank was recommended to reduce convective and conductive heat losses, thereby enhancing the performance of the system.

Technical feasibility study of net-zero energy house for Canada - case study of Team North 2009 US DOE Solar Decathlon competition

In October 2009, Team North competed in the US DOE 2009 Solar Decathlon competition. Team North's mission was to design and deliver North House, an energy efficient solar-powered home while training Canada's next generation of leaders in sustainable design. In North House, the PV system on the roof was the primary energy generation, complimented by a custom PV cladding system on the south, east and west facades. A solar assisted heat pump system, including a three-tank heat transfer and storage system, the horizontally mounted evacuated-tube solar thermal collectors on the roof and a variable capacity heat pump met the hot water and space heating demands. A second variable capacity heat pump was utilized for space cooling. The solar thermal system was studied using TRNSYS simulation. For the initial assessments the simulations were run for Baltimore. Then, the analyses were extended to different cities across Canada. In all scenarios the same house was linked to the system. The minimum annual solar fraction of the different cities was 64% and it rose up to 81%. Finally, the data measured during the competition were analyzed and compared with the data resulting from the simulation. According to competition measures, during the 10 days of competition in Washington DC, the PV system generated 271.6kWh of electricity and the solar thermal system produced 91.7kWh while the house consumption was 294.1kWh. As a result, North House was evidently a net-positive house.