Project by Ecoerne Limited & LA Plumbing & Heating

The dwelling house property, located in Derrygonnelly, Co. Fermanagh, has 22 rooms and a total heated floor area of approximately 300m2. The building was built in 2015 and is very well insulated and has a twin Nuaire mechanical heat recovery system throughout. Heat emitters are existing underfloor heating on both ground and first floor and towel radiators in the main bathroom and master ensuite.

The building is located in Derrygonnelly, Co. Fermanagh and is located 73.57 metres above sea level. Heat Engineer software using CIBSE TM36 2005 degree day data and an altitude adjustment figure established that the Design Outside Temperature (DOT) for the area is -1.64 °C. Desired temperatures of the occupants were set at 20 degrees on the ground floor and 18 degrees on the first floor, which had been the previous room temperatures for desired comfort levels.

Objectives:

– Client’s requirement for alternative to biomass wood pellets with the increasing fuel and maintenance costs. – Provide a heating system that is simple to operate and maintain and ensure high comfort levels which has a long operating life.

– Utilise the existing MyEnergi Ecosystem consisting of 20 kW battery storage and solar diverter in conjunction with 4kW solar pv array to minimise the cost of electricity for provision of space heat and hot water. – System should be capable of being monitored remotely from anywhere in the world. – Lower the building carbon footprint.

Solution:

– Install a high energy efficient Viessmann heat pump with weather compensation with convenient control via an online app.

– Installation of a weather compensation sensor would ensure maximum efficiency by modulating flow temperatures based on external temperatures. – Remove the existing towel radiators and replace with electric thermostatically controlled ones and therefore isolating from the existing space heating underfloor circuits.

– Utilise thermal imaging camera to establish retrofitted underfloor heating circuits and gather information on loop spacing and lengths. Open Energy Monitor (OEM) kit installed to give the installer and homeowner an in depth look at the heat pump’s performance and track energy and efficiency trends using the live online heat pump league on https://heatpumpmonitor.org/ to compare COPs (Coefficient of Performance) and SCOPs (Seasonal Coefficient of Performance). – Capable of viewing the live COPs & SCOPs https://emoncms.org/app/view?name=MyHeatpump&readkey=4fd57ac2f4073ca518d2956300cacc9d

Project Detail:

Viessmann’s specification for the 8kW Vitocal 150-A R290 model (Vitocal 150-A Air Source Heat Pump | Viessmann UK) was analysed which confirmed that this particular model could provide a 6.5 kW rated heating output at Air -7 / Water 35 (A-7/W35) which confirmed that it was the appropriate size for providing 100% of the space heating and hot water provision for the building and occupants at the desired outside temperature. This detailed room-by-room heat loss assessment data was then inputted into H2X (h2xengineering.com) design software to establish a heating design to ensure correct pipe sizing and ensure the existing underfloor heating pipe centres and floor coverings could provide the desired room temperatures. Pipe sizing was calculated using the parameters of trying to achieve water velocities of 1 metre per second and linear pressure losses of less than 300 pascals per metre. Existing pipe centres from the ufh manifolds were confirmed using a Testo 868 thermal imaging camera and the loop patterns established. This information was retrospectively inputted and aligned in the H2X software to enable analysis of the system design to establish that the index circuit had a linear pressure drop within the capabilities of the Viessman circulating internal unit pump.

Water Quality Treatment:

Mindful of Viessmann’s requirements to follow the VDI 2035 guidance for the filling of the heating system and the prevention of scale formation and corrosion another one of Ecoerne Training’s graduates, Terry Harvey c/o Magnetic (Int) UK (Magnetic (magnetic-online.de)), joined the installation process to introduce the 5 step process to water quality treatment.

The 5 steps being

1. Test

2. Filter

3. Demineralise

4. Ongoing Protection

Test Step 1: Having already established that the existing system water was to be drained and flushed due to the presence of inhibitor, it was important to know what the hardness and acidity of the mains water that was going to be used for filling. The water hardness was recorded at 14 °dH (degrees of German Hardness) which is considered to be medium to medium / hard and had a corresponding electrical conductivity reading of 496 µS/cm (micro siemens). The acidity was measured at a pH of 7.2. Systems of this size both in specific system volume, and heating output may not need any further intervention but it was preferred that no chemicals were to be used, therefore the system would benefit from demineralisation to ensure that the electrical conductivity was brought below 100 µS/cm and maintained at this level whilst the ph was to be maintained between 8 and 10 (there is no aluminium in this system which requires tighter pH parameters).

Steps 2 and 3: These two steps took place at the same time. The system was filled with tap water and when pressurised, the water was filtered and passed through a ‘mixed bed resin’. The mixed bed resin removes the mineral content of the water and thereby reduces the electrical conductivity. The process ran until the electrical conductivity was brought down to 36 µS/cm. Bringing the conductivity below 100 µS/cm (low salt environment) prevents corrosion, biological fouling and scale build up.

Step 4: Having achieved the desired operating conditions it is imperative that we maintain them. This is achieved by ensuring any top up water is already demineralised before it enters the system. To do this, the incoming mains water is passed through a mixed bed colour change resin cartridge (VEP 300). The colour change allows us to see when the resin is exhausted and needs changing. Controlling the conductivity of the water at point of entry means that we do not have to concern ourselves with dilution or over concentration of inhibitors. The second part of step 4 is the inclusion of a degasser which also includes a sacrificial magnesium anode. Removal of oxygen is important to help control the acidity of the system. VDI points out that there is a naturally occurring process of ‘self – alkalisation’, the inclusion of a degasser and magnesium anode, in the form of an HWR 10, provides an active method of removing unwanted oxygen and controlling ph. Also containing a magnet and non-magnetic sludge removal the HWR 10 protects the system from any unwanted contaminants that couldn’t be reached in the initial filtration.

Step 5: Ongoing testing is performed at annual servicing with a simple on-site test of the water. This gives quick and accurate confirmation that the water is within the desired parameters for corrosion free operation.

Products used for this project :
Viessmann Vitocal 150-A 8kw Magnetic UK HWR 10 Plus Degasser Zeus Articulated Mounting Feet Primary Pro External Insulation IMI Statico 35 Litre Disc Expansion Vessel Open Energy Monitoring (OEM) Kit Joule High Gain 300 litre unvented cylinder

Results: The installation of the Viessmann Vitocal 150-A heat pump by Ecoerne Limited and LA

Plumbing and Heating has been completed to a high level of detail for not only the physical side of the install but also the planning and design aspects taking on board the customer’s requirements to provide one of the most efficient heating systems on the Island. Since installation from July-Dec 2024 the Viessman heat pump through ViCare app was showing an SPF Heating/DHW 5.2 With the installation of the Viessmann heat pump the building’s carbon footprint has been reduced a further 40% to 1,112 kg of CO2 emissions in comparison to the previous biomass heating. The heat pump will also benefit from the MyEnergi Ecosytem which has 20 kw of battery storage being served by a 4kw solar pv array. The heat pump will be running on Economy 7 cheap rate electric at all times either operating at night or being supplied by the 20 kw MyEnergi Libbi battery storage during the daytime.