How It Works
Any Cat natural gas fueled engine can be configured specifically for applications involving heat recovery. The engine drives a Cat generator for greenhouse facilities to produce electricity, while jacket water and/or exhaust cooling circuits are fed through heat exchangers to transfer the waste heat from the engine to a hot water holding tank. That hot water is stored and used to keep the greenhouse warm. Oxidation catalysts can be used to remove carbon monoxide, and a urea based SCR system is employed to reduce NOx to just a few parts per million. The result is an exhaust gas so clean it is piped to the greenhouse plants' roots as a fertilizer, boosting farmers' yields.
Since sizing based on heat load is the key driver, the electricity produced at a greenhouse often exceeds the local demand. Many countries throughout Europe incentivize high-efficiency electric power generation via production credits and most electricity produced is exported to the local grid. In other parts of the world, grid unreliability and pure economics are driving greenhouse agriculture toward similar solutions.
Caterpillar provides customized CHP package proposals, including the required mechanical equipment and controls to capture and transfer the engine thermal energy to a greenhouse facility. In addition, Caterpillar offers the required exhaust emissions aftertreatment, utility grade paralleling switchgear, and controls to sell excess electricity generated to the local electric grid.
The total energy cost savings of such systems can more than offset the total owning and operating costs, delivering a payback in as little as two to three years, depending on local energy pricing and policies.