We have seen some significant changes in heating in the last 40 years. I can still remember being rudely awoken by the coal man delivering coal to the neighbours. I don’t remember having coal in our house. Although I am aware that my father turned our coal bunker in to a sand pit which I have fond memories of playing in.
When I got bored or too old for the sand pit, he then knocked that down and used the remaining bricks to extend the garage. How’s that for circular economy? My father probably didn’t realise it at the time, but he was a bit of a carbon efficiency hero.
Circular Economy early adopter, kudos Dad!!!!!
My father was one for a housing upgrade or two, I think he put the central heating system in himself. I can remember countless hours playing under the floor boards whilst my dad rectified some issue with the heating. Needless to say, none of the heating pipes under the floor boards were lagged.
The energy we must have wasted under that floor.
With any heating system you will lose or waste heat in 3 main ways. Firstly, through the efficiency of your heat source. I was undertaking an Energy audit for a client who had a 102Kw boiler with an efficiency rating of 81%. The boiler had a stated serial number year of 1999. Meaning the boiler was 20 years old.
Most boilers have a 10-15 years life span. So being 20 years old either means this boiler has been impeccably well maintained or it hasn’t seen much action. Not with standing this the argument for upgrading the boiler should be an easy one. The risk of failure is high due to its age so why not replace it.
What savings can be gained from upgrading a boiler?
For ease of calculation let us assume the client used 200,000 kWh of heat per annum. To generate this level of heat the current boiler at 81% efficient would have to burn 246,914 kWhs of gas.
Where as a 90% efficient boiler would only have to burn 222,222 kWh’s of gas and would therefore achieve savings of 24,692 kWh’s per annum. Other savings are also possible through an intelligent approach to system design. For example, rather than having a large 102kw boiler you could opt for 4 x 25Kw boilers.
This would then achieve energy savings through modulation. For example, when only a limited amount of heat was required you can bring on one or two boilers to match the required load. Rather than firing one massive boiler. This option also provides resilience as if a boiler goes down the client still has 75Kw of heat.
Energy is also lost in the transportation of heat. This for me is perhaps the most infuriating energy waste because it is so needless. Unlagged pipes lose heat and that means boilers or whatever your heat source is, will have to fire more often to recover that heat loss.
The thermal efficiency of the area being heated is another area where heat is lost and similarly to unlagged pipe work it is so unnecessary. However, I won’t bang on too much about unlagged pipe work or insulation as I have previously blogged on these subjects. (See Blogs. Unlagged pipes and the energy they waste. And, Invest in Insulation).
I will say that lagging and insulation are perhaps two of my favourite energy saving technologies. Both are simple and effective, fit and forget technology that save significant amounts of energy.
Just don’t go telling any other energy savings technologies I have favourites.
More recently different types of heat sources have entered the market. We have seen a significant uptake in biomass boilers. How biomass can ever be considered renewable or green has always baffled me.
Biomass is burning wood which is a natural resource that unlike the sun or the wind will run out if we continue our journey of deforestation. Secondly, how can chopping down trees be good for the environment?
The Biomass industry has had its fair share of bad press. Many investors have been sold systems that have either been poorly specified or poorly commissioned leading to significant down time. I have known some biomass boiler customers employing full time maintenance engineers.
There must be a biomass spectrum. In that there are some people at one end of the spectrum who have had an absolute nightmare experience. However, I am sure there are others who have got biomass right. I believe biomass has been mis sold as Green.
How can cutting down trees in Canada and shipping them to Europe be Green?
More recently we have seen an increase in renewables such as heat pumps. Which come in the form of air source (ASHP), water source (WSHP) and ground source (GSHP). These technologies certainly are truly green as they utilise ambient temperature from the air, water or ground to react with refrigerated gas to provide heat.
Air source heat pumps in my experience do suffer from poor heating co-efficiencies during the winter months. This is the result of the colder ambient air. Some of the older models employ a heating element in the winter months to pre heat the incoming air supply to the coil. This element acts as frost protection and reduces the co-efficiency further.
Where as ground source and water source heat pumps benefit from the consistent temperatures present within the aquafer and the ground. As such they have a high year-round co-efficiency regardless of the falling outside temperature in the winter months.
For me the heat source or evaluating the heat source is almost irrelevant. In some ways heat sources are like Solar PV. Solar PV is amazing because it enables you to generate power on site for your own consumption. Similarly, when it comes to generating heat on site for your own consumption. There is no point if you are going to be wasteful.
This is why lagging and insulation are so important. Passivhaus buildings employ a very unique heat source, humans. Passivhuas buildings can only use their occupants as a heat source because of their far superior levels of insulation.
Therefore if you want to reduce your heating costs it is far more cost effective to improve your insulation levels.
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