Investigation of Latent-Heat Storage Systems for Green Building Applications

Abstract

In green building applications, highest energy demands are needed for air conditioning to provide comfort conditions. This study is done by using real data obtained from a prototype structure built as part of a project. The necessity of heat storage systems during the usage of solar energy and ground-sourced heat pump systems for heating is investigated in the present study. This way, various techniques used for storing heat are researched and compared. Efficiency of latent-heat storages, constituted by utilising latent heat of phase change material, is analysed. Thermodynamic analyses of the heating system combined with solar panels, ground-sourced heat pump, and latent-heat storage are conducted. Lastly for variable ground temperature and solar radiation, changes in amount of heat storage in a heat storage system are analysed. For a 6-month heating period, analyses showed that especially in winter, energy consumption in compressor shows a sharp rise. So utilising period from heat pump with low energy consumption is too short. This study focuses on energy generation from solar panels in relation to time. Thereby, supply ratios of hourly energy demand of the inspected building are investigated.

Nomenclature

A:

Area, m²

Q:

Heat, w

F_R :

Exchanger heat efficiency coefficient

H:

Global radiation, w/m²

T:

Temperature, °C

U heat:

Transfer coefficient, w/m² °C

τ:

Diffusion coefficient

α:

Absorption coefficient

u:

Useful

c:

Collector

t:

Total

f, i:

Fluid inlet

a:

Ambient

i:

Indoor