Experimental Study On A New Low-quality Natural Energy Cascade-utilizing System

Energy is one of the key factors for controlling sustainable development. Combined with China’s status quo that energy consumption has increased dramatically, in view of China’s development of promoting green architecture and meet the requirement of energy sustainable development strategic objective, relying on the "eleventh five-year plan" national science and technology support project-the key technology and equipment demonstration of building science energy- utilizing in hot summer cold winter areas. The paper studied a new energy supply system of buildings, designed a kind of new, high efficiency and can cascade utilize low-quality energy (mainly is the solar and geothermal and other renewable energy) system for heating and cooling, studied the contrast experiment with conventional heating and cooling system. The experimental results showed that the new energy supply system can achieve the purpose of saving energy and protecting environment.First, this paper theoretically analyzed the experiment system, provided theoretical basis for designing the system; and various parameters of the new energy supply system were theoretically calculated to guarantee experiment equipments matching parameters.Then, a new low-quality natural energy air conditioning system with ground source heat pump+ fan coil and the conventional split air conditioner system were built for summer cooling; a new and low-quality natural energy heating system of utilizing vacuum tube solar energy collector and ground source heat pump units as the heat source, radiant floor as the terminal device and the conventional heating system of utilizing regional boiler rooms as the heat source, heating radiator as the terminal device were established for winter heating.Finally, the contrast experiments of winter and summer were carried out respectively, and the experimental results were further analyzed.The summer experimental results showed that compared to the conventional cooling system the new cooling system can save energy 12.90%. Besides, the summer experimental results showed with the condensate temperature constant, when evaporation temperature rose 1℃, the EER of the heat pump units increased about 3%; with the evaporation temperature constant, when condensate temperature rose 1℃the EER of the heat pump units decrease about 1.4% .The winter experimental results showed that the new heating system of utilizing new and low-quality natural energy as heat source has obvious effect in energy saving compared to conventional heating system, and the energy-saving rate can achieve 30.55%; the heating method of low temperature hot water floor radiant has obvious effect in energy-saving compared to conventional heating method, energy-saving rate can achieve 18.96%;the solar fraction can achieve about 24% in Tianjin area when the new heating system at it’s typical operation days.