HVAC Design and Energy Savings through process optimization

Air Conditioning energy savings

Building Efficiency: Most of us know about "car efficiency" but hardly anyone would know about "building efficiency". Nonetheless we bring to bear dichotomy, trumpet our concern for global warming, and blissfully shutdown public buildings for a tokenism.     

The long past experience through the two contrasting economic phases, the recession period of 1996 -2002 and the economic surge period of 2003 -2008 brings-forth a reflection. Riding high on the economic prosperity our buildings have travelled far too a distance to be efficient again. Most, and in particular, the certified Green Building ones are energy guzzlers and are built with equally higher project investment costs. Our lack of concern for knowing about the building efficiency brings-in numerous barriers to energy efficiency, and majority of those are attributable to HVAC &R (Heating Ventilation Air Conditioning and Refrigeration) which contributes to about 60% energy pie for a building.   

You may like to refer to "Making of a Green Building Code" for your concerns of building efficiency, and design concerns for the HVAC Systems of your building. It's a culmination from several hundred projects, both with the green field designs and brown field optimizations, through a motley collection of intelligent building across the length and breadth of India and worldwide.  
The propounded "Green Building Code" could well be a direction towards a possible development of one universal norm on a global scale that could delineate the degree of greenness and ensure that the past mistakes are not repeated those causes irreparable damage to the global environment and generate carbon emissions by truck loads. If there were a "Green Building Code" it would have acted as a beacon of Red Flag.

Air Conditioner tyres and selection criteria are determined by the Size of the Building. Window Air Conditioners are used for single room type applications. It makes lots of noise and thus goes with lower budget. Split Air Conditioners are best suited to cool one or two rooms. Window & Split air conditioner has limited capacity application usually within 5tons. Air Cooled Ductable Split/Package Air Conditioners or Direct Expansion DX VRV (Variable Refrigeration Volume) Air Conditioner finds its application in medium size buildings due to its ease of operation albeit very low IKW/TR Energy Efficiency and thus high Electricity Bill. When building size is big enough and its air conditioning load is in excess of 200TR both the Package and the VRV Air Conditioners become hugely Energy Guzzlers with very high Running Cost. Centralized Water Cooled Air Conditioning System is the only Energy Efficient option for any 200TR plus Air Conditioning Project. It has the best IKW/TR Energy Efficiency. Most Commonly used efficient Centralized Air Conditioning Machines are Screw Chiller and Centrifugal Chiller.          

Conventional AC Design unlike Intrinsically Efficient AC Design uses higher rating Chillers that pumps much excess Cooling Energy at the "High Side Air Conditioning System" which interconnect the Building using one common network of Chilled Water Piping System that reaches at every Low Side Delivery End like in Rooms, Conference/Function/Seminar Halls, Operation Theaters etc. Thereafter the excess cooling energy is regulated using a series of Sophisticated Control Devices/ Systems. The first control device is Balancing Valve used at delivery end Chilled Water Supply Pipe to coarsely regulate supply to individual AHU (Air Handling Unit). The fine regulation at AHU or FCU (Fan Coil Unit) is done using a 3way valve that allows only the required AC energy through the AHU/FCU to the Air-Conditioned Space/Room/Hall and the balance is sent back to the System. As the System itself gets overloaded it further needs expensive Variable Frequency Drive Controls for most equipment like Chillers and numerous AHU. The Intrinsically Efficient Air Conditioning Design on the other hand pumps only the required Cooling Energy from its Centralized Chiller Plants. It's the most Efficient, Simple and easy to operate HVAC Air Conditioning System that saves huge 50% money on initial Project Cost as well as its Running Energy Bills & Maintenance Cost.      

Encon Smart Intrinsically Efficient AC Design ensures achieving SEC Norm within the limits of Green Building Code that we have done for over hundreds of Green Buildings Worldwide. Low Side Air Conditioning System Design depends upon Indoor Air Quality Norms. The simplest application is Comfort Air Conditioning System Wherein Room Temperature and Fresh Air are the only Criterion as like in Hotels, Air Ports, Malls/ Complexes/ Corporate Buildings etc. The most stringent application is with Super Specialty Operation Theater that mandate Temperature control of 21 +/- 3 Degree Celsius, Relative Humidity (RH) control between 40 to 60% with ideal RH recommendation of 55%;   Air Filtration down to 10 micron and 5micron by washable Pre Filters at AHU and then by HEPA Filters in the OT room down to 0.5microns and 0.3microns; Minimum of 50 Air Changes out of which 5 Fresh Air Changes. In-addition NABH (National Accreditation Board for Hospitals and Healthcare Providers) Standard prohibits use of any Window, VRV or Ductable Split/Package AC in any OT as those Air Conditioners are convenient pockets for Microbial growth thus not suitable for any General OT or Super Specialty OT applications.