Study On Heat Transfer Performance Of Spherical Packed Bed With Multiple Phase Change Materials For Using In Central Air-conditioning

Today, energy shortages, excessive power consumption and serious environmental pollution problems cause widespread concern. Phase change energy storage is an important way to storage energy, and an important measure of ease the energy shortage, reducing energy consumption, reducing pollution. In particular, the introduction of cold storage air conditioning to adjust balance "peak load shifting" plays an important role. Conventional phase change storage air conditioning uses a single PCM, resulting in the increase of latent heat by certain restrictions, the lower rate of phase transformation and storage volume. Therefore, this paper with the current problems analysis the heat transfer performance of spherical packed bed regenerator by using the cold storage characteristics of the cold storage sphere. By using a combination of phase change material as a coolant (Phase Change Material, PCM), water as a secondary refrigerant(Heat Transfer Fluid, HTF), spherical packed bed regenerator is adopted to carry out cold storage experiments to analyze cold accumulating release rate, storage capacity and heat transfer enhancement of the combination PCM. The major research efforts are indicated from the following aspects:(1) Elect to meet the conditions of the air conditioning of organic and inorganic PCM, PCM for selected thermodynamic performance analysis to determine the three kinds of PCM are combined, under optimum temperature for each PCM and effective utilization calculated. Using weighted average method to calculate the equivalent phase transition temperature to obtain six kinds of combinations in line with air conditioning working conditions.(2) Through the regenerator ball and ball packed bed were established physical and mathematical models, storage ball melting and solidification processes using ANSYS software to simulate, study storage ball radius, wall temperature, storage ball material, convection coefficient, Ste number to build the relationship between cold release time, the rate of solidification and melting rate of release cold storage laws.(3) In this paper, dynamic characteristics of cool storage reservoir ball was simulated. Research on the outside wall temperature, storage ball radius, the ball storage material, convective heat transfer coefficient, Ste, Fo influence of several factors on release cold storage dynamic characteristics. Summarized the law of phase transitions. Studies ball radius and reservoir storage, dynamic characteristics of cool relations. The results showed that cold accumulating release time and presented the ball diameter is proportional relationship between the size of refinement to be appropriate. Storage at 2 ℃ HTF temperature is the lowest temperature threshold outer wall, release cold HTF temperature range outside wall when in the range of 12 ℃～14 ℃, is conducive to engineering energy-saving operation,While the storage process of experimental research, simulation and experimental comparison.(4) Spherical packed bed regenerator of the storage process simulation, the effects of HTF flow and combinations of PCM and other factors spherical packed bed storage characteristics.The results show:HTF flow increased storage rate speed up, but overall small storage capacity influence, HTF to control the reasonable range; combination of PCM storage rate per a PCM were analyzed, the phase transition temperature, the higher the faster the rate of PCM storage, using a combination of PCM can be significantly improved spherical packed bed storage capacity and storage rates, and the PCM phase change temperature and HTF greater the temperature difference, the faster the rate of storage. Storage capacity packed bed with high latent heat value of the amount of PCM and PCM’s density.This paper analyzes the dynamic characteristics of cool storage ball and ball packed bed regenerator heat transfer performance, using a combination of PCM to strengthen heat transfer. It provides a theoretical basis to improve performance and regenerator PCM storage capacity and storage rates and development of great practical significance for the future storage Air Conditioning promotion.