Young Guns from IIT Bombay Work on Maximising Returns from Chillers - India Renewable Energy Consulting – Solar, Biomass, Wind, Cleantech
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Ashwin KP (right) & his colleague Rajat Agarwal – cofounders of ChillerMate


I was introduced to KP Ashwin of Promethean Energy some months back.

Frankly, at that time, I did not think much about it. The startup facilitator Intellecap asked me if I could mentor some cleantech startups. I thought that was cool, so I accepted to “mentor” him, though I had no idea how I could possibly add value – and also wondering why anyone on earth would want suggestions from someone who was not exactly a business superstar.

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Let’s just accept that the world is a  funny place.

Despite my reservations, I kept in touch with Ashwin over the next few weeks and made it a point to meet him whenever I visited Mumbai, where he works out of.

I must say this guy has been quite an inspiration. He is what you would expect an IIT-ian to be – bright, down-to-earth and hardworking (something another IIT-ian you might just know also tries to be, but fails on all three with admirable consistency)

He has qualifications that would get him a top job anywhere in the world – a computer science B Tech from IIT Bombay and an MBA from IIM A. Last I heard, India does not have anything more premium to offer in academic degrees. After working for a couple of years at the prestigious global consulting firm BCG, he opted out to work on his own.

And started Promethean Energy with an IITB colleague of his. And the two have been working on a unique heat recovery solution that could be easily retrofitted with existing chillers and air compression units.

Having been exposed to many aspects of cleantech last few years, I am convinced that the cleantech domain that has the most attractive business case is the Energy Efficiency domain. Here is an area where you need no government regulations, policies or subsidies to drive business, where capex does not run into crores, and most important, where the equity payback period could be as low as 6 months (compare this with renewable energy projects where the payback will be in the range 6-10 years, if you are lucky).

I have been reviewing his product ChillerMate last few months, and am convinced that he is working on something that can make a tremendous difference to the country’s energy consumption for the chillers.

Here’s why:

His product ChillerMate can generate up to 2000 liters of hot water per hour from a 100 TR chiller. Now, with India having an estimated 10 million TR capacity of chillers, Ashwin estimates that the total potential for heat recovery of his technology can result in fossil fuel savings of about 3 million tons per year. Even at today’s depressed international fossil fuel prices, that would translate to almost $1,5 billion savings year on year for the Indian industry.

All the above from a technology developed by a bunch of 25 year olds in association with their alma mater, IITB.

ChillerMate, developed by Ashwin’s company Promethean Energy is a simple heat recovery retrofit to chillers and air compression units that could result in significant fuel savings for a host of Indian industries using chillers – dairies and other food processing industries, hotels, pharma companies and many more.


Fuel Saving Potential for Chillers/Coolers

In most industries, there are concurrent applications of heating, cooling and air compression. Of the cooling and air utilities, a large proportion of energy is wasted via cooling towers or radiator panels.

Some estimates suggest that over 47% of the total energy involved in a refrigeration cycle is waste heat. This is primarily rejected via cooling towers or radiators.

Similarly, in air compressors, over 90% of the total energy input is wasted as heat to the environment. In this sense, compressed air is one of the most expensive uses of energy in a manufacturing plant, with estimates suggesting that only about 4% of the total energy that goes into an air compressor will be utilized in a useful manner.

Capturing the Wasted Energy – Enter ChillerMate


ChillerMate – Simple and elegant packaging, I must say


This offers an excellent opportunity to recovery heat from cooling utilities and use it at the site of hot water use. ChillerMate technology offers an ideal solution for effective waste heat recovery from chillers and air compressors.

The heat thus recovered can be used to generate hot water, which can used directly for a variety of industrial purposed, or used as a preheated water for generating steam. In both cases, significant cost savings are realized as the fuels used to heat water (LPG, furnace oil, diesel, natural gas) have seen significant increases in prices in the past few years.

ChillerMate – About the technology

ChillerMate technology, co-developed by Promethean Energy and IIT Bombay, is made specifically to recover waste heat from chiller and air compressor units. The technology has studied the challenges faced with existing solutions like Plate Heat Exchangers, Shell and Tube heat exchangers, Tube-in-tube devices, and developed a technology which offers maximum reliability and performance with minimal maintenance requirement. Built on patented Tube Tube Heat Transfer Technology, patented and developed at IIT Bombay, this technology has been tested and finetuned over 12 years in various industries and applications.

Promethean Energy Pvt. Ltd. has been ranked among the “top 10 innovative companies in the country” by Govt. of India, Stanford Business School, Lockheed Martin  and IUSSTF in 2014.

ChillerMate – Benefits and Advantages

1. Hot water at close to zero cost.

A prominent dairy pays close to Rs. 5.75 per kg of steam for heat (translates to ~Rs. 9 per kWh of heat energy). Compared to this ChillerMate recovers cost at close to zero cost. This, combined with the low capital cost involved, ensures that payback of ChillerMate technology comes in well within a year.

2. Improves chiller efficiency and reduce running costs

By taking away heat from the refrigerant, the load on the cooling towers is reduced by a similar amount. This leads to lower cooling tower costs including water treatment costs, motor and pump costs, reduced maintenance costs etc. Specifically,

  • Upto 25% increase in condenser area available for heat rejection
  • 5-20% increase in cooling capacity of the chiller
  • Reduces power consumption of chiller due to higher COP
  • All associated cooling tower costs reduced – water treatment costs, pumping costs, etc.

3. Green way to do business

By saving on the fuel that would otherwise be spent on generating the hot water, this technology helps in reducing the carbon footprint of the industry, while at the same time increasing the quota of carbon credits/ESCerts for the industry. If the certificates from the savings can become tradable, almost 30% of the cost of the unit will be paid for just by these savings.

A ChillerMate installation on a 100 TR system saves enough carbon dioxide equivalent to absorbed by 7000 trees in a year!

4. Technological superiority

Built and patented at IIT Bombay, this technology has a very strong technological foundation.

  • Very high efficiency of heat transfer – the technological innovations involved in designing the product ensure much higher heat transfer compared to standard heat exchangers.
  • Minimal intrusion to existing system – all the parameters of the existing system are left almost unchanged, so that taking away heat from the system doesn’t in any way impact the current running of the system.
  • Pressure drops on the refrigerant side are designed to be minimal to ensure that the existing system is not affected by the addition of another unit.
  • The system is modular, and can be extended to generate a higher heat load if required.

5. Reliability and long life

Most installations of ChillerMate are maintenance free and have run without any service call for close to 10 years. The product can be maintained by the regular air conditioner team as well.

The unique design of the heat recovery system ensures that there is no chance of leakage from the water side to the refrigerant or vice-versa, leading to a very robust system which can never damage the existing system.

6. Additional benefits

The system is very compact and requires very little footprint for installation. Being a heat recovery device, this product qualifies for accelerated depreciation benefits, equivalent to 30% of the product’s capital cost. This can further help brand your company as an environmental friendly image.

Getting in Touch – those interested in getting in touch with ChillerMate can of course visit their site or send a note to Ashwin – 

And for those of you who are curious to know what my sterling contribution as a mentor to these guys has been – umm…hmmm…not much really, but wait, I did contribute – I suggested the name ChillerMate to them! Now, that’s some contribution, don’t you agree?

ChillerMate Case Studies

Case Study 1 : Hotel in South Mumbai
Chiller Capacity•      R22 reciprocating compressor 60 TR (211.2 kW)
Temperature of refrigerant In/Out 95/63 ⁰C
Temperature of water In/Out 30/60 ⁰C
Fuel Savings 81 L of HSD/day
Annual Savings Rs. 14 Lakh/year (based on 2015 fuel prices)
Simple payback <5 months
Unit ran without maintenance for 11+ years!Chiller cooling improvement of 20% observed


Case Study 2: Dairy in Worli, Mumbai
Chiller Capacity•      R717 reciprocating compressor 270 TR (950 kW)
Temperature of refrigerant In/Out 115/60 ⁰C
Temperature of water In/Out 25/70 ⁰C
Fuel Savings 390 L of FO/day
Annual Savings Rs. 50 Lakh/year (based on 2015 FO prices)
Simple payback <10 months
Unit ran without maintenance for 6 years.Chiller saving of close to 15%


Case Study 3: One of largest chemical manufacturers in country
Chiller Capacity•      R22 screw compressor 107 TR (350 kW)
Temperature of refrigerant In/Out 75/60 ⁰C
Temperature of water In/Out 30/60 ⁰C
Fuel being saved Briquette (Rs. 1.7 per kg of steam – 2014 prices)
Annual Savings Rs. 11 Lakh/year of briquette
Simple payback <12 months
*In process of fabrication currently – expected to be installed by April 2015

About Narasimhan Santhanam (Narsi)

Narsi, a Director at EAI, Co-founded one of India's first climate tech consulting firm in 2008.

Since then, he has assisted over 250 Indian and International firms, across many climate tech domain Solar, Bio-energy, Green hydrogen, E-Mobility, Green Chemicals.

Narsi works closely with senior and top management corporates and helps then devise strategy and go-to-market plans to benefit from the fast growing Indian Climate tech market.


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