Feasibility of ground source heat pump using spiral coil energy piles with seepage for hotels in cold regions

Abstract

Ground source heat pump (GSHP) using energy piles is a clean and efficient air conditioning technology. However, this system may suffer annual soil thermal imbalance when it is applied in buildings in cold regions, causing cold or heat accumulation in soil and having effect on the system's long-term operation. To simulate the system performance and investigate system feasibility in Chinese cold regions, a system simulation model is established considering important influential factors of energy piles group. The system is applied in a hotel of four typical cities (Harbin, Changchun, Shenyang and Beijing). The dynamic building load is simulated which shows that the hotels in four cities are heating-dominated with load ratios of 6.78 in Harbin, 6.51 in Changchun, 2.94 in Shenyang and 1.20 in Beijing. Results show that GSHP system using spiral coil energy piles is efficient and only consumes 51–62% power of conventional Boiler + AC system. When GSHP is applied in hotels in cities with similar climates to Harbin and Changchun, the soil thermal imbalance with serious cold accumulation will cause the heating performance decline as well as the heating deficiency. When GSHP is applied in hotels in cities with similar climates to Shenyang, the soil thermal imbalance with cold accumulation will cause the heating performance decline but the system's heating capacity is acceptable. When GSHP is applied in hotels in cities with similar climates to Beijing, the soil thermal imbalance with slight heat accumulation will increase the heating performance. This work contributes to the performance prediction and application guidance of GSHP systems using spiral coil energy piles in cold regions.