In defense of design 1

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Was consulted by Mr Amar Kohli, Panchsheel on the prohibitive running cost of his Gas fired 389 litre boiler based residential heating system. Tragic – but as I explained to the plumber and to Mr Kohli, there were a number of design weaknesses in his current installation which were responsible for a high running cost of 1 cylinder/day! At Rs.450/- ($10) per day that is almost a whopping $300/- per month expense!!

Ashwini Agarwal Solar

What were these design weaknesses? Firstly, the pipe dia from the gas geyser to the house was 1″ – we normally give a 1/2″ design and that means that he was having to cover 4 times the dead-spill water and two times the heat loss! Also, since he was using a circulating pump, the water in the pipe length – my estimate is approx 150′ =22 litres! – would pump back in his main tank and then he was mixing approx 2-300 litres of cold water in the tank every 24 hours!

Good engineering is good design and good workmanship combined. I have recommended that he reviews adding a SWHS in a series design so that he feeds hot water into his current system and dramatically slashes his heating costs. And aim at taking the first 20 litres of cold water out into watering his garden/other uses. My current analysis is that with some prudence he can cut down on his heating costs to 20% of the current expense.

Sometimes, money just cannot make up for poor design!

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