Part 1 Solar Thermal
Slight departure from the gardening theme today folks.
In these times of rising energy bills I thought I’d share a few short posts on the energy saving measures we have set up around the house and how they have helped to keep our energy bills under control.
Today I’ll talk about our solar thermal system, and in future weeks I’ll cover rainwater collection and how we manage to heat the house.
It was always planned as part of the lifestyle change to reduce our reliance on the utility suppliers and to try and find ways to reduce our carbon footprint which was huge at the time as John spent a fair amount of time traveling in the UK and the US.
Rather interestingly … some 5 years later the single biggest measure we undertook to reduce our footprint and had the biggest impact is growing our own food. So if you do nothing else I urge you to start a vegetable garden.
I never really thought of our lifestyle change as an exercise in ostentatious living, more an attempt to learn how to create a more sustainable and ultimately cheaper lifestyle for my family.
When we built the house we decided to invest in as much ‘green’ technology as we could afford but only in measures that we felt could make a tangible difference to the household finances.
Well, we’ve now been in our house for just over 4 years and have learned an enormous amount about generating your own energy a d I thought it might be cool to share some this good stuff.
Going off grid.
Whilst we may have once dreamed of going completely off grid (zero dependency on the utility companies) … in reality we weren’t quite ready for it. That’s not to say we won’t one day number number of things have to come to pass before we reach that milestone, not least the technology is not quite there yet.
How to generate hot water from the sun – Solar Thermal
The single biggest change I’ve noticed in the last 4 years in both myself and the rest of my family is an increased awareness of where our energy comes from and how much of it we use.
In this first of our posts I’ll take a look at solar thermal and what difference (if any) it’s made to our bills.
To accompany the post John has made a short video which is available on our You Tube channel that should help to unravel some of the mysteries around solar thermal and how it works.
When we built the house we installed two solar thermal panels on our East facing roof. Each panel is made from a series of copper pipes encased in what is essentially a black metal box. The front of each panel is covered in toughened glass and connected to the other via a standard 15mm mm copper connector.
Feed and return pipes are run from the inlet on one panel and outlet on the other all the way back to the hot water tank in the utility room. The feed and return pipes are super insulated to stop heat loss, and to protect against scolding, which is just as well as well as the pipes can reach over 85C when the sun is at its hottest!
There is a small controller unit back at the hot water tank which manages the flow of any hot water from the panels to the hot water tank.
How does it work?
When the hot water tank senses the water in the panels is higher than the temperature in the tank a small pump next to the hot water tank kicks in and circulates the liquid through the hot water tank via a heat exchanger (basically a series of copper coils inside the tank) and transfers any generated heat to the rest of the water inside the tank.
How efficient is solar thermal?
It’s during the summer months the panels provide the most financial benefit as we pretty much turn the oil fired boiler off most days between May and early September … providing the sun shines of course!
It’s all relative when it comes to solar thermal. The hotter the panel gets the more heat is transferred to the hot water tank, but you can only use as much s you can store in the tank at any one time.
I’ve found the secret is to try and utilise the stored hot water in the morning and leave the rest of the day for the tank to heat up again. Of course that’s not always possible but it’s the most efficient way I’ve found to make the most of the free energy.
On a sunny day the two panels produce enough hot water for our 4 bedroom house, but in the winter months we rely almost totally on the the oil fired boiler to heat the water. We do have occasional sunny days in the winter, which are welcome, but only really supplement supplement our needs.
The panels cost us around £2,500 along with the solar controller and connectors. My brother in law handled the plumbing which was around £250. John installed the panels when we built the house, so total cost for our completed system circa £2,750 excluding John’s time.
Benefits of installing solar thermal?
For us it’s primarily about saving money on our oil bills, but at the same time it’s really important to us to reduce our reliance on depleting fossil fuels for our energy needs.
We pay an average of 64p a liter for our oil, which works out to around £512 for 800 litres.
During the summer months we believe we save in the region of 800 litres of oil, which if you do the maths means it will take us just under six years to recoup our investment. After that it’s saving all the way!
Final thought on Solar Thermal …
When you come to sell your property having solar thermal can be a great selling point, especially when you tell the buyers they have had no capital outlay and every tank of hot water generated from the solar panels is free!
Of course not everyone wants panels on their roof, but better designs are emerging all the time and personally I don’t find them overly offensive, but appreciate they may not be for everyone.
The set up we have is extremely efficient and cost effective method for supplementing our hot water needs, especially in the summer months when there is lots of lovely warm sunshine, but in the winter you will need an alternative fuel source such as gas, electric, wood or oil.
If your interested in installing a Solar Thermal system I go into more detail in the first of our energy videos, which you can find on our You Tube Channel www.youtube.com/ruralgardeners
In the mean time if you have any questions please do drop me a line, or leave a comment and will endeavor to provide some answers.
Next time we’ll be sharing our experiences with rainwater harvesting.