US: Hybrid chiller leverages multiple energy sources

"Growers are now able to use a chiller that's powered by a natural gas engine. When using natural gas during operation, the heat is captured off the engine, and indoor and greenhouse farms can utilize this byproduct for domestic hot water, dehumidification, space heating, and any other need in the facility. Capturing the heat increases the efficiency to over 80%, dwarfing the efficiency of the grid power production and, in turn, cutting back on Scope 2 emissions," says Stephen Lafaille, VP of Business Development at Tecogen.

Recently, Tecogen introduced the 'first Hybrid-Drive Air-Cooled Chiller in the US.' Similar to a plug-in hybrid car which can leverage multiple energy sources, this air-cooled chiller has the capability to run on 100% electric, 100% natural gas, or any combination of the two fuels.

Able to adjust in real-time, the chiller can adapt to inputs from the utilities or the building to decide which fuel source would be optimal for the priorities of the customers. Plus, with the ability to black start and run off the grid, growers can count on Tecogen's Tecochill chiller to be reliable even during outages.

Automated optimization
While the grid transitions to renewable sources, using the Hybrid-Drive chiller will allow growers to adapt to the composition of the grid or the cost of energy. Throughout the day, there are several reasons to run on electric or natural gas.

For example, the Tecochill chiller would adapt to inputs of demand and energy price fluctuations and transition to running on natural gas to avoid high electric costs. These also happen to be times in which the carbon intensity of the grid is quite high. "Another operational mode would follow every facility's individual need for hot water. In each CEA farm, the need for heat varies greatly, so Tecogen designed the chiller to be able to seamlessly start up the natural gas engine to produce enough hot water to fill the current need," Stephen adds.

Cost saving ability
"CEA customers can find a 40-60% operational cost reduction by utilizing Tecogen's efficient Tecochill chillers. When powered with natural gas rather than electricity, Tecogen's units can provide cooling at a significantly lower cost than conventional electric chillers. Greenhouse and indoor farms can realize additional savings when using the free engine waste heat byproduct," explains Stephen.

This efficient simultaneous use of the engines' shaft power and captured waste heat is considered a form of "mechanical Combined Heat & Power (CHP)" by utilities and government agencies. As a result, Tecochill chillers can qualify for significant state, federal, and utility incentives. These incentives can reduce a facility's upfront capital investment significantly and make the payback period for facility owners with Tecochill chillers even better. Currently, there is a 40% Investment Tax Credit (ITC) offered by the federal government's recent passing of the Inflation Reduction Act (IRA) granted to all Tecogen products as well as a substantial portion of the installation cost to implement them.

Resiliency
Each year the weather becomes more unpredictable, and somewhere in the world records a new record number of temperatures, storms, fires, and floods. "The electrical grid cannot always be relied on to keep the lights on and the climate controlled. The Hybrid-Drive Tecochill chiller dual power source will continue to run without grid power using its self-generated power produced by the natural gas engine," Stephen concludes.