A Waste Heat Recovery Solution for Container Farms to Enhance Space Heating Potential

Indoor farming in modular container farms has risen in popularity over the last decade due to its ability to grow fresh produce year-round in a controlled environment. Generally, these farms require a significant amount of energy to create an ideal growing environment for plants. Heat is often generated as a byproduct of this energy conversion process and is usually rejected to the environment. To address this issue, waste heat recovery technology can be used to capture and repurpose this excess heat for other applications, such as space heating for a greenhouse. This research investigates the potential of storing low-grade waste heat in a diurnal rock bed thermal storage and utilizing it to enhance the performance of an air-source heat pump. A comprehensive energy model was developed to analyze the complex energy transfer between the various systems. To refine the energy model, a prototype of the coupled system was designed, built, and tested in Ottawa, Canada. Experimental results showed that there were improvements in the performance of the air-source heat pump when using the heat from a rock bed. However, a continuous supply of waste heat is required to maintain a consistent level of heightened efficiency. From the simulation, it was found that the implementation of the proposed waste heat recovery solution has the potential to yield the most significant benefits and cost savings in cold climate communities.