Thermodynamic and economic analysis of heat storage application in co-generation systems

Abstract

SUMMARYThe possibility of improvement of the energy performance and economic feasibility of a CHP plant by the use of hot water storage tank is analysed in the paper. An energy balance of a system consisting of a CHP module, a peak boiler and a heat storage unit has been built and the storage efficiency has been defined. Heat transfer in storage tanks and its influence on the energy balance is discussed. A numerical model of heat transfer in the storage tank is presented. The thermodynamic and economic optimum of the tank volume for a sample co-generation plant has been found. It has been eventually proved that the installation of a heat storage unit provides reduction of fuel consumption in the system.

Towards the increased utilisation of geothermal energy in a district heating network through the use of a heat storage

“…It should be noted that 3 the tank will not be always full as in the case of the stratified tank, but it will be charged or discharged with water, changing 4 the volume of stored water continuously, according to the excess or shortage of heat demand. For the calculation of the 5 temperature evolution of the stored water the following energy conservation equation is applied [21]:…”

“…This can also be 20 made clear in Figs. 7a, 7b, 8a and 8b where the cash flow charts of the middle and high sizing of the installation are shown 21 for the cases that the RHI is taken and is not taken into account, respectively. As can be seen in these graphs, the effect of the 22 these graphs in the 20 years of the investment is because the RHI is not provided after this period of time, so the income 1 consists only of the first two parts after the 20 th year of operation.…”

Optimal Configuration of the CHP System Using Stochastic Programming

“…Based on system scenarios, the LOLE for both electric and total heat demands is given by (36) Moreover, the expected energy not supplied (EENS) is considered in this paper. This index represents the average energy not supplied when there is a loss of load.…”

“…The approximate investment costs of the boiler and heat-storage tank have been extracted from [35] and [36], respectively.…”

Solid oxide fuel cell micro combined heat and power system operating strategy: Options for provision of residential space and water heating

“…The study assumed 100% efficiency of hot water storage. Reviewed articles with similar aims included Baughman et al [6] and Kostowski and Skorek [7] who considered the thermodynamic, engineering and economic optimum capacity of TES for commercial applications. Baughman et al found that addition of a cold TES to an industrial plant had a substantial positive net present value (NPV), and the addition of absorption chillers and co-generation resulted in a significant additional improvement in NPV.…”