Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Performance analysis of a solar-assisted ground-source heat pump system for greenhouse heating: an experimental study
AbstractThis study investigates the performance characteristics of a solar-assisted ground-source (geothermal) heat pump system (SAGSHPS) for greenhouse heating with a 50m vertical 32mm nominal diameter U-bend ground heat-exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir (568 degree days cooling, base: 22°C, 1226 degree days heating, base: 18°C), Turkey. Based upon the measurements made in the heating mode from the 20th of January till 31st of March 2004, the heat extraction rate from the soil is found to be, on average, 57.78W/m of bore depth, while the required borehole length in metre per kW of capacity is obtained as 11.92. Design practices in Turkey normally call for U-bend depths between 11 and 13m/kW of heating. The entering water temperature to the unit ranges from 8.2 to 16.2°C, with an average value of 14°C. The greenhouse air has a maximum day temperature of 31.05°C and night temperature of 14.54°C with a relative humidity of 40.35%. The heating coefficient of performance of the heat pump (COPHP) is about 2.00 at the end of a cloudy day, while it is about 3.13 at the end of sunny day and fluctuates between these values in other times. The COP values for the whole system are also obtained to be 5–20% lower than COPHP. The clearness index during experimental period is computed as average 0.56. At the same period, Cucumus sativus cv. pandora F1 was raised, and product quality was improved with the climatic conditions in the designed SAGSHPS. However, experimental results show that monovalent central heating operation (independent of any other heating system) cannot meet the overall heat loss of the greenhouse if the ambient temperature is very low. The bivalent operation (combined with other heating system) can be suggested as the best solution in Mediterranean and Aegean regions of Turkey.
Performance analysis of a solar-assisted ground-source heat pump system for greenhouse heating: an experimental study
AbstractThis study investigates the performance characteristics of a solar-assisted ground-source (geothermal) heat pump system (SAGSHPS) for greenhouse heating with a 50m vertical 32mm nominal diameter U-bend ground heat-exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir (568 degree days cooling, base: 22°C, 1226 degree days heating, base: 18°C), Turkey. Based upon the measurements made in the heating mode from the 20th of January till 31st of March 2004, the heat extraction rate from the soil is found to be, on average, 57.78W/m of bore depth, while the required borehole length in metre per kW of capacity is obtained as 11.92. Design practices in Turkey normally call for U-bend depths between 11 and 13m/kW of heating. The entering water temperature to the unit ranges from 8.2 to 16.2°C, with an average value of 14°C. The greenhouse air has a maximum day temperature of 31.05°C and night temperature of 14.54°C with a relative humidity of 40.35%. The heating coefficient of performance of the heat pump (COPHP) is about 2.00 at the end of a cloudy day, while it is about 3.13 at the end of sunny day and fluctuates between these values in other times. The COP values for the whole system are also obtained to be 5–20% lower than COPHP. The clearness index during experimental period is computed as average 0.56. At the same period, Cucumus sativus cv. pandora F1 was raised, and product quality was improved with the climatic conditions in the designed SAGSHPS. However, experimental results show that monovalent central heating operation (independent of any other heating system) cannot meet the overall heat loss of the greenhouse if the ambient temperature is very low. The bivalent operation (combined with other heating system) can be suggested as the best solution in Mediterranean and Aegean regions of Turkey.
Performance analysis of a solar-assisted ground-source heat pump system for greenhouse heating: an experimental study
Ozgener, Onder (Autor:in) / Hepbasli, Arif (Autor:in)
Building and Environment ; 40 ; 1040-1050
02.08.2004
11 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Performance analysis , Solar-assisted ground-source heat pump , Greenhouse heating , Izmir , EWT , entering water temperature , GHE , ground heat exchanger , GRP , glass reinforced plastics , GSHPS , ground-source heat pump system , LCD , liquid crystal display , SAHPS , solar-assisted heat pump system , SAGSHPS , solar-assisted ground-source heat pump system
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