Estimating heat losses in solar high-temperature heat accumulators based on a nonstationary three-layer model
Abstract
A model and program for numerical research on the temperature and heat losses in solar high-temperature heat accumulators (HTHAs) are developed. The model is a one-dimensional three-layer system (insulation-accumulator-insulation) constructed on the basis of a one-dimensional nonstationary model of heat exchange with asymmetric boundary conditions and includes heat losses by radiation. The model can be also used for three-layer contacting bodies. It is shown that with respect to low-temperature heat accumulators in HTHAs, the materials best suited for heat accumulation are those with high volumetric heat capacities. A one-dimensional model with an accuracy of up to 10% can be used to estimate the characteristics of real volumetric 24-h high-temperature heat accumulators, and with an error of up to 30% for 48- to 72-h HTHAs.