Study of Solar Cooling Alternatives for Residential Houses in Bahir dar city :

Sammanfattning:

The energy consumption rate of non-OECD countries rises about 2.3 percent per year as compared to the energy consumption rate of OECD countries which is 0.6 percent. If developing countries use energy efficient technology and integrate renewable energy systems in the new building their carbon dioxide emission rate reduces by 25 to 44 percent.  However, even now, renewable energy integrated buildings are hardly considered while constructing them.

This thesis work focuses on the study of solar cooling system options for residential house in Bahir Dar city. To meet the demand of housing in the city, different type of apartments and villa houses are under construction.  Case study was made focusing on two types of residential houses (condominium apartment and Impact Real-estate Villa house) to determine the cooling load and to select cooling system.

Simulation results of IDA ICE software show that the average operative temperatures and cooling loads for condominium apartment and Real-estate Vila are 31.8^oC and 30.7^oC, 5.53 kW and 5.73 kW respectively. Most of the residences are not satisfied at this operating temperature.

There are different types of solar cooling systems.  Solar Sorption cooling systems are commonly used which can also be classified in to absorption, adsorption and desiccant cooling systems.  Solar adsorption cooling systems are easy to manufacture locally as compared to solar absorption cooling systems. They do not have moving parts. Some of the working medium pairs used in adsorption cooling system are: Activated Carbon/Ammonia, Silica gel/ water, Zeolite/water. Adsorption chillier with Silica gel/ water as a working pair was selected since it can operate at regeneration/desorption temperature as low as 45^oC coming from flat plate collectors.  At 75^oC regeneration temperature, the system delivers 9^oC chilled water temperature.

The selected solar adsorption chiller has been compared with kerosene based adsorption cooling system using HOMER software.  In this project, the optimization was limited on cost comparison between the two energy sources.  The solar based cooling system has lower working cost.

From cooling load simulation result direct solar irradiation is the highest source of cooling load for both houses. This gives an opportunity for passive solar cooling technology.