With ever increasing burden on conventional energy resources and the impending energy crisis, it is all the more important that we seek alternative resources to cater to our daily demands. In this project we aim to harness the constancy of ground temperatures. The constancy of the ground temperatures can be used for the purpose of conditioning the air that we use in our homes as well as office spaces for a more comfortable living. At the depth of about 10 feet or more soil temperature remains fairly constant throughout the year. We can therefore use the ground as a heat sink for cooling in the summer and a heat source for heating in the winter. In order to use this concept, we pass the air through underground tunnels. The cooled or heated air can be used directly for the conditioned space or indirectly with air conditioners or heat pumps. This system has a very high Coefficient of Performance (COP). Length and diameter of pipe, air flow rate and initial soil temperature affects the temperature of exit air. Dehumidification and humidification are employed is necessary.

Now, let us discuss how we can use the ground temperatures for the purpose of conditioning the air that we use in our homes for a more comfortable living. The design given is simple, has an extremely low operating cost, is clean, completely quiet, and above all, it is very environment friendly. Here the ambient air is taken into an underground thermally conducting pipe labyrinth through a specially designed inlet. Certain portion of the inlet pipe is kept above the ground wrapped in canvas. This canvas is kept moist, which causes evaporative pre-cooling of the inlet air.The cooling pipe labyrinth will be placed under water reservoirs (harvesting rain water during rainy season to sustain the rest of the year) to channelize the water around the pipes through natural percolation process.If necessary this cold air is redirected into the air conditioner for further cooling.The length of the pipe underground can be increased or reduced according to conditions such as ambient air flow rate, requirement and ease of excavating ground.

Types of earth loops that could be used are: Horizontal trench loops, horizontal slinky loops, horizontal bore loops, vertical loops, pond loops, open loop-well system.

Applications are: Cooling home in summer or heating home in winter, farmers can use it to heat their greenhouses when required, heating floors of houses in cold climate, it`s a free source of energy, a complete green solution. It can either be used directly as a source of heated or cooled air or can also be used with air-conditioning units in order to reduce cooling load on the AC.