Comparisons between ground and air source heat pumps in hot/dry climates : Saudi Arabia as a case study

The use of ground source heat pump (GSHP) systems in cold climates, such as those in parts of North America, Scandinavian countries and China has been discussed for decades. However, hot and dry climates are encountered in vast regions across the globe but, unfortunately, not much data exists in terms of the GSHP systems. This paper aims to investigate the feasibility of using GSHP systems in hot and dry regions and Saudi Arabia is a case study by comparison between using a ground source heat pump and the conventional air source heat pump (ASHP) systems based on Saudi Arabia climates conditions.

In order to compare the economics of geothermal heat pump systems to other HVAC alternatives, a direct capital costs comparison is made between GSHP and ASHP. Based on the length of the ground loop, which was calculated using the ASHRAE method, the initial installation cost for GSHP leads to an increase in the investment costs of GSHP because of the extra expensive drilling costs for the ground loop heat exchanger and piping. However, over the period of approximately 22 years there is a 19.6% total cost savings using GSHP compared to ASHP and the GSHP is more feasible with a long payback period. Also, the CO2 emission decrease by about 34%.