Village at the Park Retirement Village Project, Wellington

The problem

A retirement village contacted Flow Heating to investigate heating and hot water that was not functioning correctly in one of their apartment blocks and rest home, spanning three floors. The existing system comprised two dated 80kW floor-mounted natural draft boilers running on constant flow temperature, supplying the building’s radiators and heating a 1000 litre cylinder for domestic hot water. The system was consuming large amounts of natural gas even when no heating was needed.

One boiler had completely failed and the second was close to failing, so replacement was required. The retirement village wanted to reduce its carbon footprint with an environmentally friendly solution that would also lower running costs. There was not enough power supply on site to run a full electric system without an expensive upgrade to the building’s mains supply.

Our recommendation

Flow Heating proposed splitting the building heating and hot water heating into two hybrid (electric and natural gas) circuits, working within the site’s existing power supply:

• Building heating circuit | three 16kW Vaillant Arotherm Plus high-temperature air-to-water heat pumps and a 60kW Vaillant Ecotec Plus gas condensing boiler, with Vaillant weather compensating thermostat controls.
• Domestic hot water circuit | two 16kW Vaillant Arotherm Plus high-temperature air-to-water heat pumps and a 37kW Vaillant Ecotec Plus gas condensing boiler.

Weather compensation on the building heating circuit means the system puts in only as much heat as the external air temperature requires, keeping residents comfortable and preventing the building from overheating. The system is designed so the electric heat pumps carry the load in normal conditions, with the gas boilers only switching on for peak demand or when the ambient temperature drops very low. Over two months of monitoring, the gas boilers made up 10% of total energy use and the heat pumps the other 90%. The hybrid design also gives multiple levels of redundancy, sharing the load across several appliances.

The installation

The biggest challenge was keeping heating and hot water operational throughout the project with minimal disruption, since relocating residents was not feasible. Flow Heating overcame this by setting up temporary boilers, which allowed the old boilers to be removed and the plant room stripped out to give a clear space for the new plant and equipment. Once the new plant was in place and the piping installed, the changeover to the new system was completed in a couple of hours.

Vaillant equipment supplier Waterware supported the project throughout, providing design schematics, on-time product delivery and technical support.

The result

Based on the first two months of operating data, Flow Heating is forecasting a $30,000 reduction in running cost and natural gas usage per year. The retirement village also benefits from reduced maintenance costs and a significant reduction in carbon footprint. The customer was very happy with the smooth process, minimal disruption and quality of workmanship, and was surprised at how quiet the Vaillant heat pumps are.

Commercial heating in Wellington

Village at the Park is a retirement village in Berhampore, Wellington, and this project heats an apartment block and rest home across three floors. See more of our commercial heating work across Wellington.