A novel approach to the hydraulic sizing of borehole heat exchangers (BHEs) is presented. The choice of flow rate and operating temperature of fluids and their impact on the following elements are investigated: heat transfer performance, head losses, pumping energy consumption, and the performance of coupled heat pump. Up to now, sizing methodologies investigate principally the ground behavior when heat flux is applied: desired results consist mainly in number and length of BHEs necessary to meet the thermal load. Hydraulic analysis is often rough performed. Here, an integrate modeling of the overall system are considered through an innovative set of equations. It includes main elements that determine the performance of a GSHP system: ground thermal modeling, heat transfer effectiveness of BHEs, sensitivity of the heat pump to the sources temperatures. Results shows how an approximate hydraulic sizing of a BHE field, and a decoupled choice of the heat pumps device can conduct the operating point of GSHP system far from planning condition: overall coefficient of performance is consequentially reduced.

The Impact of Hydraulic Sizing on the Performance of Ground-Coupled Heat Pump Systems

CONTI, PAOLO
2013-01-01

Abstract

A novel approach to the hydraulic sizing of borehole heat exchangers (BHEs) is presented. The choice of flow rate and operating temperature of fluids and their impact on the following elements are investigated: heat transfer performance, head losses, pumping energy consumption, and the performance of coupled heat pump. Up to now, sizing methodologies investigate principally the ground behavior when heat flux is applied: desired results consist mainly in number and length of BHEs necessary to meet the thermal load. Hydraulic analysis is often rough performed. Here, an integrate modeling of the overall system are considered through an innovative set of equations. It includes main elements that determine the performance of a GSHP system: ground thermal modeling, heat transfer effectiveness of BHEs, sensitivity of the heat pump to the sources temperatures. Results shows how an approximate hydraulic sizing of a BHE field, and a decoupled choice of the heat pumps device can conduct the operating point of GSHP system far from planning condition: overall coefficient of performance is consequentially reduced.
2013
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/654666
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