THE
Volume 9. Issue 04. April 2015 Rs. 25/-
INSIDE TRACK CONNECTING THE DESIGN COMMUNITY Now view our web edition at www.theinsidetrack.in
Cover Story
M
an has battled climatic extremes for millennia - be it the icy wastes of the cold Tundra or the extreme heat of the Sahara desert. Here in India ancient people made use of large manual fans, thatched roofs and mud huts. But in today’s modern world, we have to acknowledge the challenges that come with providing HVAC services to a large, robust economy. Of course, when developing HVAC solutions one must keep in mind the specific climatic conditions of the environment surrounding the building. India is a climatically diverse country with three major climatic zones - hot-dry, warm-humid and composite. This is without taking into account the spells of extreme cold that affects the Delhi and NCR region during winter. We take a look at how HVAC can assist in coping with the extreme climatic conditions in India.
Surviving Climate Extremes With HVAC
The right HVAC specifications make all the difference when you are tackling India’s extreme climate. BY ALYSSA LOBO An installed Coolstream evaporative cooling unit by Colt, UK
Warm-Humid
In India, the air conditioning system consumes most of the energy that a building needs in its operation. In such a case, a good HVAC system is one which reduces energy consumption in the air conditioning effort. Cities like Mumbai, Chennai and Kolkata fall under this climatic category. Therefore while designing a HVAC system one should include the following parameters: Reduce dependence on the air conditioning system in the building while designing. Recognise spaces inside the building which do not require air conditioning, as reduction in air conditioned spaces will reduce the AC consumption load and the energy needed for the same. Optimise the cooling load by selecting interior and outdoor design conditions specified in National Building Code of India 2005. The code includes a DB (Dry bulb temperature) and a RH (Relative humidity) for a variety of spaces, from restaurants to operation theatres. The cooling load can also be optimised by implementing the required ventilation rate and
An Air Handling Unit (AHU) by Daikin
pre-cooling the fresh air required to maintain good indoor air quality through heat/energy recovery from cool exhaust air Another way to boost energy efficiency is through specifications in the Air Handling Unit (AHU) - a device used to condition and circulate air as part of an HVAC system. One way to do this is by equipping the air system design to operate in 100% fresh air mode. Heat usually builds up in buildings when the air conditioning system is not working. This heat buildup affects the system’s operation the following day by increasing the cooling demand and therefore increasing energy consumption. The AHU supplies fresh outdoor air that is necessary to flush out this heat build-up. In order to maximise the effectiveness of the air flushing; all AHUs should be designed so that it operates at 100% fresh air mode to remove the heat. Energy can also be saved by using cool outside air to freshen the indoor space. When the outside air is sufficiently cool, it doesn’t require additional conditioning. This portion of the air-side economiser control scheme is called free cooling. Air-side economisers can reduce HVAC energy costs. Although all AHUs are designed for peak load condition, most operate at part load conditions. If the operating capacity of the AHUs is un-synchronized with the cooling demand, it leads to energy wastage. To combat this, AHUs should continued on page 2