Updated: Mar 21
Heat recovery can go a long way in saving you energy and money. In this post, we'll review a few options including CO2 heat recovery, process heat recovery, and free cooling.
CO2 Refrigeration Heat Recovery
CO2 is not only an environmentally friendly Natural Refrigerant, but is also capable of efficiently generating high temperature heat - more efficiently than many traditional heat pumps. The utilization of heat typically rejected to the atmosphere can:
significantly increase overall cycle efficiency
reduce dependency on fossil fuels/ natural gas
simultaneously add heating and cooling capacity with a single system
High and low-grade heat recovery options:
CO2 also allows for optimization for different applications because it can extract heat at a variety of different temperatures. For example, the configuration shown in Figure 1 shows heat extraction at three different temperatures:
165-185F Water (Sanitary Cleaning/ Space Heating)
125-145F Water (Domestic Hot Water)
110-120F Water (Low-grade/ Hydronic heating)
*May also be eligible for energy incentives to help pay for the systems.
Free Cooling and Process Heat Recovery
Another way to incorporate heat recovery and increase system efficiency is by utilizing a multi stage heat exchanger with a glycol chiller.
There are many different options to pre-cool fluids before the chiller, reducing the size of the chiller required (capital savings) and the energy use (energy savings). By incorporating sanitary heat exchangers, it may be possible to cool the product directly also resulting in additional capital and cost savings.
1. Regeneration – Is the process of transferring heat between the incoming and leaving product for processes that require both heating and cooling. Pasteurization is a perfect example, where incoming milk is pre-heated and leaving milk is pre-cooled by transferring heat between the two product flow streams. This concept can significantly reduce both cooling and heating energy, and is also applicable to many other processes in the food and beverage industry. This can result in a significant reduce the size of the cooling and heating load providing both capital cost, and energy savings.
2. The other option is to use well water (or water from a cooling tower if limited well water is available). This can be considered free-cooling as the cooling is done without mechanical refrigeration. It may be possible to add regeneration, and free-cooling (optimized for the application, as shown in Figure 2) to reduce the cooling load even further, saving capital cost by reducing the size of the chiller needed, and providing additional energy savings.
Example application for food & beverage.
Want to see how much you can save? We offer free consultations and will analyze energy and cost savings options for your specific application!