Abstract
A two grade phase change material (PCM) based on CaCl_2-water system has been investigated in a PCM--water heat exchanger. The crystallization of different hydrates of CaCl_2 extended the temperature range of heat storage and the storage stability was achieved by the application of wood chips as thickening agent. A short section of the heat exchanger tube (a few cm) can be characterized by a maximum curve of heat transfer coefficient in function of cooling time. Longer sections (a few meter) showed nearly constant heat transfer coefficient in the range of 115 +/- 25 W/m2K. The heat storage system is to be applied to store solar energy and the stored heat is used to preheat the water input of domestic hot water supply system.
Highlights
The temporal difference of energy source and energy needs made necessary the development of storage systems
The phase change material (PCM) containing only seeding crystals (Fig. 2A.) shows reliable phase change with low supercooling, but the repeating temperature peaks on the PCM temperature curve suggest the formation of different crystal phases
The heat removal is accompanied by the crystallization of different crystal hydrates and the continuous phase change widens the temperature interval for heat storage
Summary
The temporal difference of energy source and energy needs made necessary the development of storage systems. Keywords heat storage · phase change material · solar energy · heat transfer coefficient In summer the energy of the heat transfer fluid arriving from the solar collector at relatively high temperature (70 ̊C-90 ̊C) can be stored in insulated hot-water container.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
