Get out of ‘hot water’ –Design temperatures only happen a few times a year

BY ROY COLLVER

Modern condensing boiler equipment is becoming more efficient at getting all of the heat out of fossil fuels, and becoming more reliable and affordable every year. Even better, we are at the edge of innovations in control and system design that, combined with the more efficient boilers, will be soon able to guarantee reductions of over 50 per cent of energy input versus conventional heating systems – new or retrofit. Here are some well-proven concepts, backed up by new research, that prove how easy it can be.

Much of this has been said before (see Art McDonald’s excellent article in still some skeptics who doubt the efficacy of these strategies. Doubt no more! Research done in the last decade has proven some pretty basic concepts that we have been promoting for many years. Much of the information I have studied on this topic has been vetted by the intrepid researchers at the Natural Resources Canada - CANMET Energy Technology Centre in Ottawa. They generated the following chart in order to be able to more easily test appliances for part-load efficiency (refer to the CSA Standard P.10-07) – have a look.

This chart is a thing of beauty, a game-changer – it backs up what we have been saying for years, and I think it will usher in a whole new era of efficiency innovation. It distills down a whole bunch of information into an easily understood graphic depiction of how our heating systems in Canada work. Based on climate data from many major cities in Canada, the dotted red line is an average load profile for these cities and they all fit the profile very closely. To simplify appliance and system testing, the red line was broken down to three discrete load capacities, illustrating how – on average – our heating systems run at 15 per cent or less capacity for 30 per cent of the heating season; 40 per cent or less capacity for 60 per cent of the season; and at full capacity for only 10 per cent of the time. This elegant little chart directs us toward the fundamental concepts we will be using in the coming years to refine both equipment and system designs for greater efficiency. How can we take advantage of this information to make our heating systems energy misers?

Number one in importance is to stop over-sizing boilers – short-cycling boilers are big energy hogs. From the P.10

the Spring 2009 Ops Talk), but there are chart we can see that even a “properly”