Air conditioning and refrigeration today consumes more than 50% of the energy for many buildings. India’s Air Conditioning penetration is between 3-6% today against the world average of 60%. With increased affordability of air conditioners, there is going to be severe strain on the availability of electricity. Therefore, cooling systems that do not depend on electricity have to be adopted.

Adsorption cooling uses hot water to provide chilled water used for central air conditioning. The source of hot water required for adsorption cooling can be either solar or some waste heat source, thus reducing the cost of electricity significantly for cooling.

The diagram below shows the working of an adsorption chiller:

Adsorption Chiller

Oorja is now manufacturing adsorption chillers in India and can assist you in any of your solar cooling or waste heat based cooling projects.

There is a growing emphasis on utilising solar energy for industrial processes, cooking and other heat related processes to achieve energy security as well as to combat the menace of climate change and global warming. While there is a larger focus on power-generation aspect of solar energy, there are greater opportunities to deploy solar energy for heating requirements.

The following industries can greatly benefit from adopting solar technologies for their heating needs:

The following processes can benefit from utilization of Solar Heat:

Oorja offers the following three Solar Concentrators for different uses:
1. PTC 300: can generate heat up to 300 deg C using thermic fluid and up to 250 deg C with steam.

Large Aperture Parabolic Trough Concentrator (PTC72)

2. PTC18: can be used generating heat up to 200 deg C:

Rooftop Parabolic Trough Concentrator

Of three modes of heat transfer – Conduction, Convection & Radiation – the least understood is mode is Radiation, especially with regard to human thermal comfort. Thermal radiation is electromagnetic radiation emitted from the surface of a body as a result of its temperature. The picture below shows three modes of heat transfer:

As can be seen from the above diagram, Radiation does not require any medium unlike Conduction and Convection.

Radiant Cooling is based on the physical principle that bodies with varying temperatures exchange thermal radiation until an equilibrium is achieved. The principle of Radiant Cooling has been around in nature and human beings have using this principle knowingly or unknowingly for ages:

• Inner walls of the caves are at a lower temperature as the heat from solar radiation does not percolate down to these walls. In addition, these walls are cooled due to the water streams, vegetation etc.
• Snow-packed walls in buildings in 8th century Mesopotamia
• Lotus Mahal in Hampi has intricate channels along the walls through which water flowed to take away the heat from the interior.

Modern Radiant Cooling follows the same principle to cool a floor or ceiling (or even walls) by absorbing heat radiated by the rest of the room. As can be seen in the diagram below, a Cooled Ceiling acts as a heat sink for all radiant heat sources in the room (human occupant, solar radiation, equipment, walls etc.).

Note that Radiant Cooling is not a “high side” system that replaces Chiller. Radiant Cooling is a “Low Side” technology that relies on chilled water pipes to distribute cooling throughout a building rather than using chilled air and ductwork.

Radiant cooling systems rely mainly on the direct cooling of occupants by radiative heat transfer because the pipes, which are commonly run through ceilings, maintain the surface at temperatures of about 20-22 deg C. Through radiative heat transfer, people in the room will emit heat that is absorbed by the radiant cooling surface.

To manage indoor humidity levels and air quality, a separate ventilation system to supply fresh air is needed. Zoning of building can also be done due to ease of controlling flow of water.

Click here to know how Radiant Cooling works?