Background and objective: Groundwater heat pump (GWHP) system that uses the constant temperature of the groundwater as the source of the clean and renewable energy for heating and cooling, is applied as a strategy for energy saving and the CO2 reduction. In this techniq More
Background and objective: Groundwater heat pump (GWHP) system that uses the constant temperature of the groundwater as the source of the clean and renewable energy for heating and cooling, is applied as a strategy for energy saving and the CO2 reduction. In this technique, groundwater is extracted by pumping wells, passed through the heat exchanger and then returned to aquifer through the injection shafts. This research is aimed to assess the Groundwater Heat Pump (GWHP) System from hydrogeological point of view.
Method: Regarding the mathematical similarities between transport of the heat and mass in porous media, the applied computer code of MT3DMS in mass transport modelling, was used in this study for simulation of the heat transfer in the groundwater system to assess the GWHP from hydrogeological viewpoint.
Finding: The results show that a thermal plume is developed around the injection well due to the energy exchanges in GWHP system. This plume is regarded as an indicator of the impact of the injected water temperature on the underground source. Its extent and direction which are directly affected by the hydrogeological parameters is not fair from the heat transport aspect and finally the performance of the GWHP system.
Discussion and Conclusion: Modelling results clearly show that with the change in hydraulic conductivity in relation to the type of the sediments in porous media, hydraulic gradient and porosity of aquifer, the extent of the thermal plume is changed, expecting impacts on functionality of the GWHP system. The results of the study can be used in utilization of the GWHP system in the country, of course after the technical-and-economic justifications.
Manuscript profile
Background and Objective: This study aims to investigate a Ground-Coupled Heat Pump system with vertical U-bend heat exchanger which can provide the energy needed from the depths of earth. Exergy of the system was analyzed and the performance efficiency and coefficient More
Background and Objective: This study aims to investigate a Ground-Coupled Heat Pump system with vertical U-bend heat exchanger which can provide the energy needed from the depths of earth. Exergy of the system was analyzed and the performance efficiency and coefficient were obtained. Method:In Larijan village, due to hot springs in the area, exergy analyses of two Ground-Coupled Heat Pump systems with vertical U-bend and open loop heat exchangers were compared. Energy, exergy, entropy and enthalpy equations of both Ground-Coupled Heat Pump systems were applied and results were presented based on geographic and climatic conditions of Larijan region. Results:Moreover, it was found that the maximum exergy losses in both systems occurres in the fan condenser. Conclusion: The results show that, due to higher temperatures (the temperature of the ground or the hot spring), the performance coefficient and the efficiency of geothermal heat pump system with the open loop heat exchangers are higher.
Manuscript profile
AbstractConsidering the scarcity of natural fossil energy and dispersion of pollutant gases from their products,it seems utilizing cheaper and cleaner energy sources such as geothermal energy are vital.One of the applications of geothermal energy is geothermal pumps. Th More
AbstractConsidering the scarcity of natural fossil energy and dispersion of pollutant gases from their products,it seems utilizing cheaper and cleaner energy sources such as geothermal energy are vital.One of the applications of geothermal energy is geothermal pumps. The compressor of geothermalpumps utilizes the thermal energy of the earth to provide thermal load and hot water for the buildingsby consuming electricity. There are two most common geothermal heat pumps including a systemwith vertical and horizontal ground heat exchanger.In the present study, in ventilation calculations, the required thermal load of a typical four-story 12-unit residential building located in the East of Tehran was calculated separately based on the actualoperational data. Each story has an area of 565 square meters. According to the thermal properties ofsoil and the annual average temperature of the abovementioned area, the appropriate geothermal heatpump was selected. Subsequently, three scenarios were created through Perform software on the basisof the primary costs of purchase and installment of geothermal heat pump and its electricityconsumption. The cost-effectiveness of the studied system with that of the previous one was comparedtechnically, economically and environmentally on the basis of carbon credit costs in the world market.The results of this study indicate that the application of geothermal heat pumps decreases the totalemission of pollutants across implementing the project by 3759 tons of CO2 equivalent. Furthermore,67,000 giga joules of natural gas will be saved at the end of the project.
Manuscript profile
In geothermal heat pumps, the heat exchange with ground is performed by the ground heat exchanger. In fact, the ground heat exchanger is installed to extract or inject the thermal energy from/to the earth. The borehole depth of this heat exchanger has a major effect on More
In geothermal heat pumps, the heat exchange with ground is performed by the ground heat exchanger. In fact, the ground heat exchanger is installed to extract or inject the thermal energy from/to the earth. The borehole depth of this heat exchanger has a major effect on the system investment cost and operation; thus, this parameter must be computed with a high accuracy. There are various methods to compute the borehole depth of ground heat exchanger. The geothermal heat pump capacity and the regional soil characteristics are the main parameters which affect the borehole depth and size of the ground heat exchanger.
In this paper, the important soil characteristics are first introduced. Then, the main five methods for computing the borehole depth of ground heat exchanger are investigated with their effective parameters. Finally, these methods are compared and their application priority is determined.
Manuscript profile
Sanad
Sanad is a platform for managing Azad University publications
