CRD Ground Loop & Heat Pump Configuration 5

Question 1

During a thermal response test (TRT), what two key ground parameters are determined?

Accepted Answer

Ground thermal conductivity and borehole thermal resistance

Answer

A TRT injects or extracts heat at a known rate and measures temperature response over time to calculate ground thermal conductivity and borehole thermal resistance.

Question 2

A header manifold in a parallel ground loop field is sized primarily to:

Accepted Answer

Ensure equal flow distribution to all parallel bore circuits

Answer

Proper manifold sizing and reverse-return or balanced-tee design ensures equal flow through each bore, preventing short-circuiting of cooler or warmer fluid.

Question 3

What is 'undisturbed ground temperature' (UGT) and why is it critical in loop design?

Accepted Answer

The native soil temperature before system installation, representing the baseline for heat exchange calculations

Answer

UGT is the soil temperature before any system influence; it sets the source/sink baseline that determines heat pump COP and required bore length.

Question 4

Which of the following best describes the 'EWT' that appears on a heat pump performance data table?

Accepted Answer

Entering water temperature to the heat pump from the ground loop

Answer

EWT (Entering Water Temperature) is the ground loop fluid temperature entering the heat pump's water-to-refrigerant heat exchanger, directly affecting rated capacity and efficiency.

Question 5

What happens to heat pump heating COP as entering water temperature (EWT) decreases during cold winters?

Accepted Answer

COP decreases because the temperature lift the compressor must overcome increases

Answer

Lower EWT means the refrigerant must evaporate at a lower pressure, increasing compressor compression ratio and work input, thereby reducing COP.

(CRD) Certified Residential Geothermal Designer Practice Test

(CRD) Certified Residential Geothermal Designer Practice Test

CRD Ground Loop & Heat Pump Configuration 5