Energy Efficient Air Conditioning System Using Geothermal Cooling-Solar Heating in Gujarat, India
It is well known that one unit of electrical energy saved is equal to more than two units produced. One way of economizing the power is utilization of energy efficient systems at all locations. In the present study, the air conditioning system is analysed and an innovative way is suggested. We use natural low temperature of shallow sub surface (1 - 3 m) of the earth—geothermal cooling system. It is known that majority of the households and the apartment complexes in India have two tanks for water storage. One is the underground water sump and the other is the overhead water tank. In our study, we use these two water storage systems for space cooling during summer and also for heating during winter. The main aim of our paper is air-conditioning of the space in an economic way to save electricity. It is based on a simple idea of transferring the low temperature from underground water sump to the room in the house using water as a mode of transport. Since India is a tropical country located at low latitude, most of the year, the air temperature is high and demands space cooling. However, for a couple of months during severe winter months (Dec.-Jan.) at Ahmedabad, heating of the space is required. For heating the space, we suggest to use the well-known solar water heater. Effective use of heat exchanger is shown through computation, modelling schemes and lab experiment. We recommend geothermal cooling for 10 months in a year and solar hot water system during 2 months of winter. It is observed that the ambient air temperature of 35°C - 40°C in the room can be brought down to 26°C without much consumption of electricity. In a similar manner, the room temperature at night (13°C) during winter in Ahmedabad can be increased to 27°C through circulation of water from solar water heater in the heat exchanger.
Ground Coupled Heat Exchanger Air-Conditioning System : A Study
This paper provides a literature survey on “Ground Coupled Heat Exchanger Air-Conditioning System”. The study indicates the use of earth as a heat-sink with an aim of controlling global warming and moving towards a greener air-conditioning technology. Measurements show that the ground temperature below a certain depth remains relatively constant (15 °C-20 °C) throughout the year. This is due to the fact that the temperature fluctuations at the surface of the ground are diminished as the depth of the ground increases because of the high thermal inertia of the soil. The difference in temperature between the outside air and the ground can be utilised as a preheating means in winter and pre-cooling in summer by operating a ground coupled heat exchanger.
Numerical simulation, technical and economic evaluation of air-to-earth heat exchanger coupled to a building
An air-to-earth heat exchanger (ATEHE) consists of pipes buried in soil. We have evaluated the technical and economic performance of an ATEHE coupled to the system for heating or cooling of a building that uses 100% fresh air as heating or cooling medium during winter and summer. The soil is divided into elementary layers. The problem solved, is non stationary; however, steady state-energy equations are used for soil layers in each time step. It is found that the use of the ATEHE covers a portion of the daily building needs for space heating or cooling. The cost of the ATEHE energy is lower for summer than for winter.