A large amount of Brazilian electricity consumption is building related, and mainly consumed by air-conditioning systems due to the warm tropical weather; therefore, geothermal energy piles integrated with heat pump seem to be an interesting alternative for the building cooling demand in this country. Tropical residual soils in unsaturated condition cover a significant part of the Brazilian territory, and due to the alternation of dry and rainy periods the groundwater level and the gravimetric water content of the soils vary seasonally. Considering that the efficiency of energy piles as heat exchangers is highly dependent on soil thermal properties, which in turn rely on the soil saturation, to evaluate the seasonal effects on the thermal response of energy piles in a typical site of Brazilian unsaturated tropical soil, an extensive program of field tests and monitoring supplemented by laboratory work was carried out during a period of four years, and is reported in this paper. The results demonstrate that the thermal response of the energy pile investigated is variable throughout the year. The thermal conductivity of the soil surrounding the pile determined at the end of the rainy season can be reduced approximately 32% at the end of the dry season. This finding indicates that the seasonal variation of soil thermal properties should be considered in the design of GSHP systems with energy piles in similar soil and climate conditions.

巴西大量的电力消耗与建筑物有关，主要由于热带气候温暖，主要由空调系统消耗；因此，结合了热泵的地热能堆似乎是该国建筑物制冷需求的一种有趣的替代方法。处于非饱和状态的热带残留土壤覆盖了巴西领土的大部分地区，由于干旱和雨季的交替，土壤的地下水位和重量水含量随季节变化。考虑到能量堆作为热交换器的效率在很大程度上取决于土壤的热特性，而土壤的热特性又取决于土壤的饱和度，以评估在巴西不饱和热带土壤的典型场所中能量堆的热响应的季节性影响，在四年的时间内，进行了广泛的现场测试和监测计划，并辅以实验室工作，并在本文中进行了报道。结果表明，所研究的能量堆的热响应全年变化。在雨季结束时确定的桩周围土壤的热导率在旱季结束时可降低约32％。这一发现表明，在具有类似土壤和气候条件的能量堆的GSHP系统的设计中，应考虑土壤热特性的季节性变化。结果表明，所研究的能量堆的热响应全年变化。在雨季结束时确定的桩周围土壤的热导率在旱季结束时可降低约32％。这一发现表明，在具有类似土壤和气候条件的能量堆的GSHP系统的设计中，应考虑土壤热特性的季节性变化。结果表明，所研究的能量堆的热响应全年变化。在雨季结束时确定的桩周围土壤的热导率在旱季结束时可降低约32％。这一发现表明，在具有类似土壤和气候条件的能量堆的GSHP系统的设计中，应考虑土壤热特性的季节性变化。