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Condensing Boilers:
Many new gas and oil boilers are designed to operate so much more efficiently than the more traditional design of boiler, it is well worth considering updating your boiler, even if you leave the rest of the heating system alone.
Whereas traditional boilers were maybe 75%-80% efficient, i.e. wasting up to 25% of heat overall, condensing boilers can achieve over 90% efficiency.
This is because the hot gases which would normally just be expelled through the flue are rerouted over an extra heat exchanger and the heat recovered is used to start to heat the cooler water returning from the radiators back to the boiler.
By recovering some of the otherwise wasted heat, more of the energy used by this boiler is turned into usable heat rather than just being sent out of the flue outside.
Solar Powered Water heating
Everyone is familiar with the arrays of tubes or flat-panels now frequently seen on peoples roofs. The latest generation of panels really do work well and can provide a reasonable amount of hot water, especially during the summer.
We find that often no other form of heating is required for hot water from May through to September. During the less sunny winter months, the panels will contribute a little, but their effectiveness is less and the demand for heat is greater. A second source of heat is required.
Solar panels supply their heat to a heat-store. A large tank of water which can be heated up quite hot and then is used itself as a source of heat for the other hot water you need. At it’s hottest, the water you use will need to have cold added to make it cool enough ! If you have more than one solar panel, then more heat can be supplied to the heat-store and the system will provide sufficient heat for a bigger part of the year and a larger share during the Winter months. You need to bear in mind that the heat-store will need a place to go and could be quite large. If you have an existing hot-water cylinder, it is possible that a heat-store could go in the same place.
Any other forms of heating water can be plumbed-in to also supply heat to the heat-store and in-fact there could be maybe two others. For example, Wood burning stoves, heat-pumps, conventional boilers, etc could contribute.
There are loads of companies out there hard selling these products at quite high prices. It’s vital to make sure that the assessment of suitability for your building is done by someone who does not stand to lose a sale if you don’t go ahead with a solar powered system. Then you can be sure they are advising you to go ahead justifiably and with a system that’s right for you.
If the panels stand more than 200mm away from the roof-line or walls, you will need to get planning permission, which is likely to be approved, but may take a few weeks.
Corbel would be happy to advise you independently and manage the installation of the whole system.
Ground Source Heat Pumps, Air Source Heat Pumps and Water Source:
Ground source and air source heat pumps are a super-efficient form of electrical heating. They use a bit of electricity to pump a liquid around the system, just the same as your fridge would. Heat is extracted from the ground, outside air or water and that is used to heat your building. For every bit of electrical energy you put in, you can get up to an annual average of 3.5 times as much for free from the ground and a bit less from the air source.
In other words it’s like a fridge, which is cooling down the outside world and the heat it has to take away to make the world outside cooler is brought into the building and piped through your radiators. If you have ever felt how warm it gets behind your fridge where the little radiator grille is, then you’ll understand.
Electricity is of course a relatively expensive fuel to be using and certainly isn’t very efficient in the amount of carbon necessary per Kilowatt of energy you consume. However, when you do the sums, ground source heat pumps do work out very cost effective to run and have relatively low carbon compared to other fuel sources because you are getting so much bonus heat from the ground from a carbon-neutral and free source.
(Link to table showing the figures)
Ground source heat pumps need you to have a lot of pipe-work installed under the ground to do the extracting of heat from the ground (or even a pond or stream). The bigger your building, the longer the pipe. The pipes are buried quite deeply, so you can still use your garden.
The system works almost as well all year round, because the ground maintains a pretty constant temperature at that depth.
If you are relatively short of space outside or don’t want the disruption to your garden of installing a pipe to a big area, the pipe-work can be set into a vertical bore-hole or holes drilled down maybe 50m deep, but obviously that tends to cost a bit more.
A fluid is circulated in the pipes and that is generally used to heat hot water and radiators or under-floor heating systems. Underfloor does work well with heat-pumps, because they work even better at the lower temperatures used for under-floor heaters.
Where radiators are to be used, it’s best to redesign the system so they are bigger radiators which can then make your room just as hot but operate at a cooler temperature themselves.
Its the same with the Hot water system which is better operated cooler. Don’t listen to people who say that heat-pumps can’t get the water hot enough. Of course they can, but they work less efficiently the hotter you go, so a rethink is needed. Water doesn’t need to be as hot as we have it all the time, so the system can be designed to work cooler and so within the more efficient zone. You are less likely to burn yourself on the water, but the system does need to do a quick boost once a week to kill any bacteria that could survive the lower temperatures. That will costs few pounds a year in electricity so no major problem in our opinion.
Not all heat pumps are the same and it is well worth investing in the latest technology which have better pumps and so give more free energy for each amount you have to pay for. Get good advice and don’t buy cheap. A more efficient system will pay back the difference pretty quick anyway.
One advantage of heat pumps is they can often be run both ways around and used for cooling the building down like air conditioning in the summer, although from an sustainability point of view, we‘d rather people just open the windows than consume more electricity !
Corbel work with industry leading equipment suppliers to provide reliable and state-of-the-art systems.
Under-floor Heating.
This is a great way to heat some rooms rather than using traditional wall mounted radiators. They could be considered to contribute to efficiency marginally. The heat is evenly distributed around the room at floor level, so peoples perception is often that the room feels warmer at a slightly lower room temperature.
The slab which makes up the floor is heated up and tends to act as a storage of the heat for longer.
During installing, the floor needs to be dug up and it is an ideal opportunity to put in floor insulation, which will benefit efficiency of the building overall.
Installation however requires a significant amount of upheaval, as the floor must be lifted and then re-laid. It’s not a cheap option.
The heat will usually come from a fluid based system and sections of under-floor can be added into an existing radiator based heating system.
Electricity can also be used to put a heating element under the floor to warm tiles, but these are not particularly efficient.
Coverings: The floor is acting as the radiator, so will work best if the floor covering is tile, stone or vinyl. It is possible to put wood or carpet over the floor, but we would generally not recommend. It would be like hanging things on your wall radiators. The thing still gets hot, but doesn’t work as well in heating your room. Wooden coverings need to be a special type to minimise warping.
Combined heat and Power (Domestic and small scale):
CHP systems as they are generally abbreviated are capable of taking some of the heat or the waste heat from the boiler part of the system and using it to generate electricity. These already work well on a large scale and there are one or two systems available domestically.
Oil powered power generating units are available, which use the heat from the generator to supply heat for the heating system. If your building is slightly larger or you are radical enough to set-up an arrangement between neighbouring properties, then viable systems are available.
High efficiency solid fuel heaters:
A range of super-efficient wood burners are available by import which burn all forms of timber in a way which maximises the heat output and burns the timber completely to leave a tiny residue of ash. The benefit is less fuel being consumed and less ash to dispose of. The systems store the heat produced for longer, releasing it slowly rather than losing most of it up the flue.
Although these units are quite good looking, they are not as aesthetically pleasing as a traditional stove or wood-burner and are intended to be more functional as an efficient heater than a centre-piece to your living space.
Corbel can look after installation of these and other wood-burner and stove systems. We can make sure the chimney is suitable and lined as necessary, taking care of any associated chimney/building works if required.
Better control of heat usage:
Quite often with existing heating systems the controls of what gets heated when the central heating is on are fairly crude. In many cases it may just be on or off at certain times once or twice a day and the temperature for the whole building controlled by one thermostat based on the air temperature in one room.
With better control systems, less heat will be wasted. The easiest change to control would be to add individual thermostats to each radiator so that each can be controlled to switch-off when the desired temperature for each room is reached.
More modern and more sophisticated controllers can allow you to set the pattern of heating so that the on and off periods are more controllable. Also with some more complicated changes to the pipework and adding some valves, zones or heating could be created so that, for example the bedrooms in a house weren’t switched on until later in the evening or just the downstairs rooms were heated during the day at the weekend.
This kind of control is required on new-builds but would be of benefit in existing systems. |
