Name: Mr Marks
Location: Hoole, Chester
Technologies Installed: Solar PV, Solar Thermal, Mechanical Ventilation Heat Recovery, Underfloor Heating, Ground Source Heat Pump
We were contacted in 2017 by a client (Jeremy) who was looking to complete a full renovation of a 1970’s bungalow in the leafy suburb of Hoole in Chester. The client was gutting the property and essentially starting again, he was interested in future-proofing the property and had renewable technology in mind to help do this. He was looking to reduce his overheads as they settle into their retirement home.
After undertaking an initial site survey to determine what kinds of technologies would benefit the property, we got started on our proposal.
The project started in the summer of 2017 with extensive building removal works required prior to TGG getting on site.
After assessing all the information collected during the site survey, we decided that a 6kW Solar PV system would work well for this project. The system would be made up of 20 x 300w Perlight mono modules and a SolarEdge 5000W inverter.
PV Roof Works – July 2017
The solar thermal and solar PV roof works were installed first before the new extension construction began. Each only taking us a day to complete. Pre-insulated pipe was installed in the loft for the thermal system.
Solar PV Inverter and Commissioning – September 2018
Following the roof works over a year previously we were finally in a position to finish of the PV installation.
The solar PV system will provide around five thousand kilowatt hours of electricity every year. This will be used in the property when there is a demand (i.e. heat pump is running or kettle is on). This reduces the amount of electricity imported from the grid and in turn reduces electricity bills for the property. The system components come with a 12 year warranty and the system will last in excess of 20 years.
To further improve the property’s energy efficiency, we also proposed to install 1 x FK 500 Portrait Collector 2.51m2 In Roof solar thermal panel on the rear roof of the property. The system was proposed to be installed on the South West facing roof to maximise the energy from the sun throughout the day especially in the afternoon.
This solar thermal installation would contribute around 30 – 50% of the total hot water demand, and should allow him to turn off the gas boiler during the summer months. A Flat plate planet was also selected to match the current look on the roof of the proposed PV system.
The Solfex flat plate solar thermal panels were installed above the roof (rather than in the roof). It was secured to the roof using steel brackets and aluminium profile bars. From the roof 20m of DN 16 pre-insulated thermal pipe was routed back to the garage where it was connected to the twin line pump station. The pump station was then connected to the twin coil cylinder and controlled by the Delsol controller.
The Solar Thermal system will generate around 1,500kWh’s of heat energy every year. The system also qualifies for the Renewable Heat Incentive which supports the installation of renewable technologies. The client will receive annual payments of around £300 plus savings of around £200 per year.
For the heating system the client had a keen interest in trying to use a renewable heat technology and had heard about heat pumps as a new technology.
Having had previous experience of using boreholes for drinking water at a previous property, Jeremy was keen to see if boreholes could be used to collect heat for a ground source heat pump.
After assessing the site and speaking to the drilling contractors it was agreed that despite the suburban nature of the property, it would be possible to get the rig in and get suitable boreholes installed.
We proposed to install a 22Kw Ground Source Heat Pump central heating and hot water system. The proposal included the installation of one Eco Forest 22kW Ground Source Heat Pump, 2 x 125m Boreholes, 1 x 400 litre DHW hot water cylinder.
All this would supply 100% of the central heating and hot water for the property.
The GSHP system is eligible for the Government’s Renewable Heat Incentive (RHI) which will pay the client up to £5k per year for 7 years.
GSHP Boreholes – October 2017
We waited for a few months until the site was ready for the boreholes to be drilled. When drilling 125m boreholes the machinery required is considerable and it was a bit of a squeeze when we saw the 40ft wagon arriving! However the drilling contractors were brilliant and had the kit offloaded and operational in a few hours.
Borehole one proved to be a little tricky as the guys encountered a boulder of some sort and needed an additional drill bit. Borehole one took a full week, borehole two only a couple of days. Within two weeks the boreholes were done and guys and all kit off site.
GSHP – Plant Room Installation – September 2018
As soon as the UFH pipework was completed we were straight onto the GSHP installation. The Ecoforest GSHP unit, 200 litre buffer, and 400 litre DHW cylinder were all positioned and plumbed in.
As you can see from the pictures our installation team take great pride in providing a neat and tidy installation that works. To get the plant room operational took a couple of weeks.
The Ground Source Heat Pump system will provide a a low carbon and low cost per kilowatt hour heating system. The client pays around 15p/kWh and the GSHP efficiency is 4:1. So the actual cost per kWh is 15/4 = 3.75p/kWh. However the PV system will actually supply a portion of that energy for free! The system was eligible for the Renewable Heat Incentive (RHI). The scheme is similar to the Feed-in Tariff in the way that it pays out for every bit of energy produced by your renewable heating system, and the client will receive quarterly payments for the next 7 years!
Part of the brief from Jeremy was that he required UFH throughout the property. Whilst retrofitting UFH is a little more challenging than fitting for new builds it can be done with the right approach.
We proposed that the existing 50mm of screed was dug out taking the floor back the slab and then we would ‘pinch’ 20mm of the existing room height. This would allow us to install 30mm Kingspan insulation, the UFH pipes on top and then 40mm liquid screed followed by final floor finish.
UFH Pipework and Screed – August 2018
The Greener Group were contracted to provide the full UFH installation including insulation, waterproof membrane, pipework and screed. Following the removal of the old screed layer and some works to patch up the floor to make it level and smooth, we got cracking.
The insulation went down in no time, being very easy to work with, it was the waterproof membrane which was time consuming. Every room needs to be ‘tanked’ to allow the screed to be poured in with no leaks.
Once the membrane was down we moved on to fitting the UFH pipework. Over 1km of pipe was laid throughout the property using staples to hold in place. Then comes the moment of truth the screed being poured in.
Due the height restrictions we had in place a liquid screed is used, allowing a 40mm covering over the insulation. It is a more expensive choice but perfect for this application. It also dries more quickly than a traditional screed.
The screed went in perfectly, credit to the screeders! Especially considering the floor was not completely level with it being an old property with two extnesions.
An aspect of UFH which is often taken for granted is the control system. We opted for the Heatmiser system with wired thermostats. With 12 zones including 3 bathrooms care was taken to make sure these all corresponded correctly and operated when required.
If care is not taken in this area the unfortunately familiar circumstance of “it’s not my job” or “they didn’t tell me this” can occur. Working closely with the on site electrician made sure the whole system integrated correctly.
Underfloor heating is a great way to get heat into the fabric of a building and provide a lovely even temperature throughout. It works particularly well with heat pumps as it is designed to keep the property at a constant temperature, with gradual climate adjustments as required (just like a heat pump). It allows for low flow temperatures (35 to 40 degrees) compared to radiators (50 to 70 degrees) which is conducive to low running costs. And of course there is no need for radiators which frees up all kinds of wall space!
To give a lovely feeling in the house and fresh air throughout we also recommended a Nuaire Q-Aire MVHR system with summer bypass and integral humidistat wall mounted in the loft of the property. Working closely with Nuaire we designed a MVHR branch system to supply the property with fresh air and extract smells and heat from the bathrooms.
Installing MVHR as a retrofit technology is tricky because generally there are ceilings in place. By the nature of the system the vents need to come into the rooms via the ceilings, and in turn all the ducting is out of sight in the loft. Yes it was a very hot a sweaty two weeks in August in a loft for the TGG installers! Aside from the uncomfortable working conditions the kit went in successfully. Once pipework and electrics were completed a day was spent on site commissioning and balancing the system.
MVHR is there to provide ventilation for the property. Often a requirement on new build houses due the air tightness, it is designed to move air around. It filters the fresh air being brought in so helps with air quality and can help against allergies. The Nuaire system also has heat recover meaning that any heat taken from bathrooms and kitchens will be fed back into the property.
The Greener Group have been installing renewable energy technologies since 2010 and have gained a wealth of experience over the years. Working with residential and commercial clients to guide and inform, we take a project from design to completion. If you are considering a renewable energy system for your property please get in touch to discuss the project.
If you would like to discuss how any of these renewable technologies could work for your property, please contact one of the team.