Research On HVAC Design Of Complex Buildings In Severe Cold Area

China is a big country with rapid development of construction industry,and the annual growth of building area is the fundamental reason for the annual increase of building energy consumption.For complex large-scale public buildings,due to its various functions and huge energy consumption of building equipment system.its HVAC system accounts for about 60%of the total energy consumption of buildings.At the same time,the proportion of heating energy consumption in severe cold area is huge,and the energy consumption per unit building area is 1-2 times higher than that in developed countries.In the design of HVAC of public buildings in severe cold area,the central heating is generally used as the heat source in winter,and the cold source unit is used as the cold source in summer,so there is a hig difference between the cold and heat loads.However,there is a prominent contradiction between improving or improving the indoor thermal comfort level and indoor air quality and reducing the building energy consumption.This paper takes a public building in Changchun as an example,and takes one year as a cycle:simulate the whole working condition of the indoor and outdoor environment of the building to get the load and load change trend of the building;simulate the air conditioning system and evaluate the system with unnsatisfied hours;compare different schemes of heat and cold sources to get the energy-saving scheme;and Three kinds of HVAC schemes are respectively simulated and analyzed to determine the energy-saving design measures;using the life cycle cost method,the annual cost of the system is analyzed to complete the design.Though the above cases,a complete design process and energy-saving scheme for the HVAC system design of large complex public huildings in the severe cold area have been formed,which provides an important reference for the design of public buildings in the severe cold area.The conclusion is as follows:Aiming at the target building studied in this paper:the comfort of fan coil plus fresh air system is poor,but the economy is good;on the premise of meeting the combination,the power consumption of three units in parallel operation is smaller than that of two units in parallel operation,and the COP value is higher.In view of the complex building HVAC system in the cold area,the following improvement measures are put forward:using the total heat exchanger or exha’ust heat recovery technology to reduce the fresh air load;reducing the energy consumption of the refrigerator,reasonably selecting and matching the unit;using the frequency conversion fan and frequency conversion water pump to design based on the principle of "large temperature difference and small flow".