Homeowners Professionals

2020 HV News Award - Renewable Project of the year

The new build property was one of 5 houses being constructed on a small development in Barnsley with ambitions to exceed the building regulations requirements with regards to fabric insulation levels.

Project Overview provided by Matrix Energy

Originally the client only wanted to have a  ground source heat pump  without using any other technology, but, as the development was taking shape and we worked on other properties, the client started to take more interest on what we were doing for other people.

On one property we installed integrated PV roof panels as the customer knew what they wanted; for the client it was too late to install integrated roof panels. We therefore had to install an ‘on roof’ system as the roof slates had already been installed.

Once interest for the PV had taken shape, the client wanted a battery installed to take maximum benefit from any PV generated.

Matrix Energy Systems understand a great deal about the holistic process for a heat pump solution and select a technology mix based on the best fit for each individual property. Ian already knew he wanted to achieve better results from building fabric than the existing standard in the UK, the software we use allowed us to modify insulation designs by creating different wall material make ups to generate varying U Values to give a Peak Heat Loss – See section 3.

The property was modelled to use a flow temperature of 35 degree celscius by using  underfloor heating  both upstairs and downstairs, the low flow temperature and weather compensation allowed the heat pump to run a maximum seasonal efficiency.


The Solution

There was not enough land at the property to use surface collectors, therefore Matrix had to explore the suitability of drilling for a borehole installation. The Geological surveys showed heavy coal mining in the area, but at a depth below 140m.

Matrix designed the system to be drilled to 120m which was more than was needed; we did this because the added length would raise the fluid temperature coming back to the heat pump. For every 1 degree celcius above 0  degree celcius the power output of the heat pump increased by approximately 3%, this giving extra output for free and hence further increasing the Season Performance of the System.


  1. Viessmann Vitocal 222-G: 6kW GSHP system (7.2kW due to borehole depth) Integrated 220L DHW Cylinder
  2. Viessmann Vitocell 100-E: with 200L Buffer Vessel
  3. Pearlight Split East/West PV Twin MPPT: 4kW
  4. Sonnen Batterie 9.43 V9.0: 5kWhours

Energy and Environment

Every consideration is given to energy and environment at Matrix as we use an advanced piece of software to model all customers projects, the software is called CYMAP and is a steady state modelling system that allows us to visualise the project in CAD and then apply insulation values to all the fabric elements.

The extra insulation added had reduced the peak heat loss of the property to below what thestandard building regulations would have delivered by almost 2kW peak demand.

Energy Use  

Matrix installed their own energy monitoring system in the property to monitor energy consumption around the system as well as MCS accredited metering, The MCS accredited metering was not required for the system.

The Matrix system is run using ‘Python’ software and was programmed internally to take readings from multiple sources around the building. These have been compared to the readings from the MCS accredited metering and are within the MCS tolerance range to be deemed acceptable.


The project design was completed in August 2018 and borehole drilling commenced quickly after. The connection to the house was completed and filled in straight away, no trace can now be seen of the borehole of the interconnection to the house as it is all buried.  


The GSHP consumes 1.5kW of power when running at its designed output for the system in winter. The solar PV system is more than capable of covering this power requirement as it can deliver a peak of 4kW power to the property. The PV system only need to be operating at 38% of its peak capacity to cover the usage of the heat pump.


Matrix were very clear with the client that the PV system will not be as good during winter and that obviously and consumption at night would have to be from the grid. This is the reason for the client choosing a battery system.

The 4.0kW Solar PV array was installed using two peak power trackers on an East / West pitched roof. The PV array was installed just in time for the March 2019 deadline for the FIT using an ‘on roof’ system.

We pointed out the benefit of generating electricity while consuming it using the heat pump and the decision was easy for Ian to make after installing the solar PV.

A 5kW hour Sonnen battery was installed in order to maximise the storage of electricity for the property. The battery system is completely modular and can be expanded up to a maximum capacity of 15kwHours.

The Sonnen battery is intelligent and is able to identify components around the property, recognise their consumption data and only allow them to operate if enough storage is available to run them free from grid usage, for example a washing machine, dishwasher or tumble dryer; the heat pump is also set up to run in this way for as long as possible.

The Sonnen Battery also has a smart grid function that will allow the end user to export and import energy on a private Sonnen network which will be more cost effective than the national grid, this system is available in Germany now and will be released in the UK in the imminent future.

The Viessmann system and UFH system can be controlled via app on a smart phone as well as the Sonnen battery, therefore all systems can be remotely accessed, monitored and manipulated. We have also provided graphical data from our data capture system installed on the project. This project has only just gone live and therefore we have picked a day that at least had a small activation for heat.

The data will also be used to determine the benefits of the battery system to the end user and give data with regards to likely storage and generation for future purchase of an electric vehicle.

This system uses free electricity where it can and minimises the use of grid electricity. When it does use grid electricity, the  heat pump is operating at maximum efficiency  in a building designed to beyond standard building regulations.


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