━━━━━━━━

Renewable technologies working together

Project Overview

When planning a major rebuild of his current home, Rev. Iain Rennie wanted to “do his bit” towards reducing CO2 emissions, whilst keeping his utility bills to a minimum during his retirement. Viessmann specified an integrated system of renewable solar thermal, solar PV, and heat pump technologies which now saves approximately three tonnes of CO2 annually.

An integrated solution

Previously, the heating and hot water in Rev Rennie’s 1940s three-bedroom property had been provided by an oil-fired boiler. At very low outdoor temperatures, the heat pump is supported by an auxiliary in-line electric heater. For the majority of the year, this also helps the heat pump operate at its peak output.

The lowest-cost energy source

During solar gain, the integrated control system suppresses the heat pump and instead collects energy from Viessmann Vitosol 200-F solar panels on the roof. This ensures hot water is always generated by the source with the lowest-cost. At other times, or when demand is greater than can be satisfied by the solar system, the heat pump is brought on-line to top up the Vitocell 300-B 300 litre hot water cylinder which stores the home’s hot water. An integrated renewable system of solar thermal, solar PV and heat pump technologies for this
Re-modelled 1940s home was recommended.

Solar PV and heat pump technologies save approximately three tonnes of CO2 annually.Renewable technologies working together Electricity is produced on-site by a combination of theinitial 2.25 kWp Vitovolt system, which has since been augmented by a second array as more roof space was created by additional building work. The harvested energy is fed back to the heat pump to further reduce its cost of operation, or back into the mains grid at times of surplus

Compatible products, significant results

The heating system is now harvesting 25,720 kWh of free energy from the ground and running at a seasonal performance of 2.25 COP. Solar PV panels are also generating around 3.3 kW of electricity over the two arrays, with the solar thermal (for hot water) and solar PV systems working together to reduce CO2 production by 3 tonnes per year. Compared to an oil-fired boiler, the installed system is costing 45 percent less to run, the equivalent of £972 per year.

Without any incentive payments, the installation costs would be recouped in around 20 years, but support from the domestic Renewable Heat Incentive could reduce this by half when introduced. The customer already receives Feed in Tariff incentive payments for the two Solar PV arrays, and the government’s Renewable Heat Premium Payment has already paid £1,250 towards the heat pump and £300 for the solar hot water installation.

18th century watermill replaces oil heating
with water source heat pumps

━━━━━━━━

Project Overview

The Grade II listed 18th century watermill is situated on the picturesque River Stour. The river was originally diverted to feed the millpond and water was controlled by a sluice gate under the property, where the original millwheel is still housed. The owner, knowing that his 20 year-old oil-fired heating system would need replacing before too long, had been thinking about using the river water as a heat source. “I couldn’t bring myself to replace our oil boiler with another oil boiler,” he said. After a conversation at the Ecobuild exhibition, the owner was able to confirm that ground source heat pump technology using river water as a heat source, was indeed viable.

One of the main challenges was deciding on the best location from which to abstract the river water. Ultimately, it was decided that the millpond at the entrance to the mill wheel was the optimal place. To prevent build-up of river silt and pond weed wrapping itself around the equipment, the owner decided to have the pond dredged and to modify the existing pond level retaining wall. He also built a second protective wall, so that the filter is housed between both walls, with a small volume of continuous water flowing through the bases to disperse silt.

The two Vitocal heat pumps were located in the existing plant room, taking the place of the old oil tank and boiler, with separate heating and hot water flow/return underground pipes to the house. The owner was pleased that through a carefully worked plan, the new installation while keeping the old system operational, and so maintaining an uninterrupted supply of heating and hot water.

How the system works

The system operates via a high volume, low pressure pump that draws water from the river, pumping through the water / brine plate heat exchanger to extract heat. About 20 percent of the water is returned to the river water intake filter unit as part of the self-cleaning process. The filter removes river sediment, down to extremely fine particles. The cooler water is then returned to the river about 10m downstream. The installation operates in a master slave configuration and distributes heating via a Vitocell 950 litre buffer cylinder and hot water storage is in a Vitocell 300-V 500 litre cylinder.

The property has three existing heating circuits, including underfloor on the ground floor, which are now managed by Viessmann’s Vitocom 100 controls, and which can be fully accessed over the internet by the owner from a mobile app. A Vitotrol 300 wall-mounted control in the house also allows for instant operation of the system.

Project Overview

When the Chapelfield Veterinary Partnership opened the Brooke Veterinary Surgery equine clinic, it wanted a heating system with significantly lower running costs than its five other practices, which are all run on oil-fired boilers. The Partnership extensively researched possible options for heating systems for the new build development near Norwich. A Vitocal ground source heat pump (GSHP) and 400-litre buffer vessel were used to provide the high volume of hot water required during surgery hours and maintain a consistent temperature in the building for the animals and their owners throughout the year.

The site incorporates consulting and treatment rooms, an operating theatre, pharmacy, reception area, offices, and a waiting room, and is surrounded by fields, which offered the perfect opportunity to install a state-of-the-art ground source heat pump renewable heating system. The innovative heating system also includes a 24 kW cooling function and is now saving the Partnership £4,744 per year compared to the oil boilers at other sites.

Vitocal meets the specification

As a lot of surgery takes place at Brooke, the comfort of the patients and staff is vitally important. In light of this, the Partnership highlighted the need to have a reliable heating system to continually run at an ambient, but adjustable temperature. It stipulated that it wanted to make use of the 3 acres of land around the surgery. To fulfil this brief, Viessmann recommended a 21 kW Viessmann.

Vitocal 300-G GSHP with 1200 metres2 of ground loops, which were installed in the field adjacent to the main building. The heat pump automatically adjusts between winter and summer months via the Vitotronic controller, so no maintenance is required from the owners. A Vitocell 400 litre buffer vessel was also installed to manage the high water demand. To make the best use of Viessmann technology, an underfloor heating system was fitted into the ground floor of the building, covering an area of 240 metres2.