Study On Geothermy Source-Floor Radiant Heating System

Standing column wells in groundwater source heat pump is one kind of geothermy source heat pump with high efficiency in exchanging heat, the application of which is just in a preliminary stage in China. This well system has been applied for a long time abroad, while at present in China, the study of its theories and tests is almost blank. Thermosyphon-embedded floor radiant heating is a novel heating system with high efficiency, low energy consumption, and beneficial to protect environment. There were few related reports on study and application of this new radiant heating system not only domestic but also foreign.Therefore, a serial systematic and comprehensive study on standing column wells in groundwater source heat pump and thermosyphon-embedded floor radiant heating were expanded in this dissertation. The main work and results are listed as follows.1. The establishment of one-dimensional transient heat-transfer model for standing column wells in groundwater source heat pump and the analysis of its characteristicsi) Mathematical model was established to describe the one-dimensional transient heat-transfer process between the well water and the soil around. Limited discrete method was adopted for numerical calculation, ii) It was found that the temprature of far boundary played very critical roles in the heat-transfer process though the setting of its boundary should not be unlimited but within the influencing scope of the well-water temprature under the condition of 5℃temprature difference between the supplying and recycling water in heat pump. The initial temperature had no impact on heat flux,which was influenced by the size of the well and the water velocity in it. Compared with the depth of the well, the size of its radius obviously exposed more influence on the operation time, iii) the initial temperature, well water velocity, and its diameter and depth had influences on the heat-extracted high-point of the standing column wells.2. Experimental investigation on thermosyphon-embedded floor radiant heating.Experimental system for thermosyphon-embedded floor radiant heating operating with ground water heat pump was built in this dissertation. Temperature distribution and heat transfer rate of thermosyphon-embedded floor, indoor air temperature, and performance of ground water heat pump were tested at different working conditions. Experimental results indicated that: i) thermosyphon-embedded floor has high heat transfer efficiency and good thermal storage capacity, ii) temperature gradient at human altitude in thermosyphon-embedded floor heating room is fairly small, iii) standing column wells in groundwater source heat pump working with thermosyphon-embedded floor radiant heating can not only satisfy the demand of heating system, but also perform well.