Estimation of In Situ Heat Capacity and Thermal Diffusivity from Undisturbed Ground Temperature Profile Measured in Ground Heat Exchangers

Heat Transfer Modeling of the Ground Heat Exchangers for the Ground-Coupled Heat Pump Systems

Ground-coupled heat pump (GCHP) systems have been gaining increasing popularity for space air conditioning in buildings due to their reduced energy and maintenance costs. The efficiency of GCHP systems is inherently higher than that of the traditional options because it utilizes the ground which maintains a relatively stable temperature all the year round as a heat source/sink. Compared with tr...

Improvement in Modeling of Heat Transfer in Vertical Ground Heat Exchangers

The heat transfer model of vertical ground heat exchangers for ground-source heat pump systems is discussed. An explicit solution of a finite line-source model has been derived to better describe temperature response of boreholes for long time steps, which can be easily incorporated into computer programs for thermal analysis of ground heat exchangers. A quasi-three-dimensional model is also pr...

Literature Review on the Calculation of Vertical Ground Heat Exchangers for Geothermal Heat Pump Systems

The calculation of Ground Heat Exchanger (GHE) performance is very important for predicting the performance and estimating the initial cost of geothermal heat pump systems. In North America it is estimated that on average GHE are oversized by about 10% ~ 30%. A vertical Ground Heat Exchanger (VGHE) is most common because of its smaller environmental influence and land field requirement. This pa...

Systematic errors in ground heat flux estimation and their correction

[1] Incoming radiation forcing at the land surface is partitioned among the components of the surface energy balance in varying proportions depending on the time scale of the forcing. Based on a land-atmosphere analytic continuum model, a numerical land surface model, and field observations we show that high-frequency fluctuations in incoming radiation (with period less than 6 h, for example, d...

Thermal and Hydraulic Performance of Heat Exchangers for Low Temperature Lift Heat Pump Systems