Studied On Cool-Storage Air-Conditioning System Of Microencapsulated Phase Change Materials Slurry

At present, our main grid loading rate decreases year by year, and the difference between peak and valley grows more and more. In order to ensure grid safety and stable operation, it promotes all kinds of peaking technology. Therefore, the research about storage air-conditioning technology has some practical significance and economical and social benefit.Storage air-conditioning not only achieves peak load shifting of power load and ease the power supply contradictions, but also has lower investment comparing with other measures. The most commonly used cool-storage air-condition is ice storage air-condition which has low phase change temperature, low coefficient of performance of refrigeration units, high energy consumption. Cool-storage air-conditioning system of microencapsulated phase change materials (MPCM) is a new type of energy storage air-conditioning system, which the phase change material is encapsulated by microcapsules with the encapsulation technology and through the melting and solidification of phase change materials to storage latent heat of phase change. In this paper, the phase change materials are higher carbon hydrocarbons that have higher temperature of phase change. Such phase change materials have the benefits such as larger latent heat, cleaner, higher temperature of phase change and small specific volumetric dilatation. In this paper, advantages and disadvantages, the development of the background, status and application prospect of MPCM are preliminarily introduced, and the application in air-conditioning field is presented particularly though researching the phase change materials and the microcapsule technology.Establish the exergy analysis model for MPCM storage air-conditioning system and analyze the exergy loss of the system. Find the ways to improve the heat economy of circulatory system from a qualitative point of view. And it makes comparisons among MPCM storage air-conditioning system, ice storage system and conventional air conditioning system. The result shows that the exergy loss is the lowest and the exergy effciency is the highest.When MPCS(microencapsulated phase change materials slurry) replaced water as the fluid medium, though the physical parameters of MPCS to research and analyze the impact of specific heat and latent heat value on slurry flow rate, viscosity on the pipe resistance, heat transfer coefficient on the fan coil tube area, as well as factors on the pump energy consumption. From the fluent sumilation and the analysis about MPCS, the area of the coil is not significantly increased and the resistance loss of the coil is enlarged a little, but the pumps'power is reduced.Dry coil runs in dry conditions, so there is no condensed water and mold, and has better health conditions. It needs the chilled water having higher temperature comprised with conventional coil. This paper describes a complex system that MPCM storage air-conditioning system combined with dry coil system. This system makes a six-floor hospital building located in Shanghai as the case to analyze, and fixes room parameters and fresh air volumes. Using the Energy plus to simulate the hourly energy consumption throughout the year, and then to do hydrographic computation and choose the equipment. Under the premise of meeting the requirement of air-conditioning, this complex system improves air quality, achieves peak load shifting.Optimize the storage strategy of MPCM to make the system better play out of its own superiority. Analyze the different concentrations of MPCS to determine the most economical and practical concentration, which is0.4, and compares with the water about the impact on the pump energy consumption. Though the economic analysis of the case to calculate the annual cost and compare with conventional dry coil system.MPCM storage air-conditioning system is a new air-conditioning system, and it has its own unique advantages compared with ice storage and water storage. Although it is still in the research stage, it has better prospect. It not only can ease the power pressure, shift peak load, but also keep the refrigeration unit running efficiently. Combined with dry coil technology also can save energy and improve indoor comfort level.