How Windham Hospital Replaced their Chiller
Hospital achieves 85% efficient cooling and heating, while relegating their boiler to a backup role
HOSPITAL: Windham Hospital had three choices when it came to replacing their aging absorption chiller. (Courtesy of Tecogen)
Windham Hospital is a 130 bed community care hospital which was first opened in 1933. As part of the Hartford Healthcare network, they are committed to the quality care and safety of the community. Part of that commitment is the reduction of public health risks caused by their environment.
To take preventative action against their scope 2 emissions, Windham Hospital decided to help improve the community’s health by implementing an engine driven chiller. On this campus, Tecogen runs one 200-ton Tecochill chiller to provide a consistent more efficient cooling and heating base load during the air conditioning season.
Tecochill chillers are powered by robust and efficient TecoDrive engines, an industrialized V8 that Tecogen has spent decades perfecting for this application. With over 80 million run-hours, this is a proven engine design and includes high part load efficiency, heat recovery, and emissions control.
When it came time to replace their aging absorption chiller, Windham Hospital had three choices: direct absorber replacement, bring additional electrical capacity to power an electric chiller, or drop in a low-electric Tecochill chiller. To achieve their timeline, sustainability, and budget goals there was only one answer: a Tecochill chiller. Utilizing this engine-driven chiller allowed them to skip waiting for the utility because it only needs 2kW to run. The Tecochill was eligible for an incentive making the installation costs comparable and by using an engine-driven chiller they were actually reducing their carbon footprint by relying less on the grid electricity.
On February 3rd 2023, New England reached one of it’s coldest days of the year averaging less than 20oF and dropping below 0oF all night. In contrast, on June 19th 2024, New England saw a new high for the date reaching 98oF. While you could have felt the obvious difference in these days, the hidden distinction was the energy generation needed by the grid.
HOT COLD: A comparison between hot and cold days. (Courtesy of Tecochill)
8,843 MW of extra power production was needed between the two seasons, but what causes this huge rise in demand? The answer is based on the needs of people. In the winter, people need heat which is produced by on-site oil or natural gas combustion in over two third of commercial buildings. In the summer, people need cooling which is run off electricity in 99% of commercial buildings. What becomes apparent is that the electricity needed to power the air conditioning is actually falling on the responsibility of the grid, and what is shown by the ISO-NE fuel mix is that the increased demand for cooling is actually being powered by natural gas. Of the 8,843 MW increase in demand on the grid, you will find that natural gas covers and actually surpasses that increase as oil and other resources are used less as well. This means that those 99% of commercial buildings are not only using natural gas for their cooling but are using it at a 40% efficiency with no way to use the thermal energy byproduct and with a 5-7% loss as the electricity travels to the building.
With Windham Hospital swapping to engine-driven cooling, they are expected to save 200 tons of carbon emissions annually by using natural gas directly and efficiently. While utilizing the free heat recovery for their domestic hot water, they are able to achieve an 85% efficient cooling and heating system while also relegating their boiler to a backup role.
On top of the sustainability benefit, Windham Hospital is able to reduce their cooling related operational costs by around 50% because of the low cost of gas and high cost of electricity in Connecticut. Their project criteria was achieved.
Looking for a reprint of this article?
From high-res PDFs to custom plaques, order your copy today!
