Potential for Savings Using a Gas Booster Heater in Commercial Dishwashing Applications

Restaurants and institutions with high-temp commercial dishwashing equipment must rinse dishes in water that is at least 180° F in order to sterilize them, according to code requirements. A booster heater is needed in order to raise the temperature of the water coming from the service water heater to the required level. Booster heaters generally use electric resistance immersion elements to heat the water, but gas booster heaters have recently become available. Gas booster heaters could be expected to use less total energy than electric units given the generation and transmission losses inherent in electrical power. They might also help to reduce utility system peaks and environmental impacts. As a result of the way electricity is charged for, electric booster heaters can represent a substantial expense to the restaurant owner, especially if the heaviest booster heater use occurs when the building is experiencing its overall maximum use (or peak demand). The impact of booster heaters on several businesses' electric bills was evaluated, along with the savings associated with using gas booster heaters. Electric load monitoring equipment was installed in 5 restaurants and institutions over a 6 month period in 1990. In addition, data from two restaurants involved in a previous study were analyzed. Three of the seven restaurants had booster heaters which made a significant contribution to the overall building electrical demand. In these cases, the paybacks on the installed cost of using a gas booster heater were between 0.8 and 6.0 years depending on the model of gas booster heater selected. An important result of the study is that monitoring of the electric booster heater and building loads is needed to determine savings from installing a gas heater, and savings calculations are not simply a matter of subtracting the rated electrical load of the booster heater from the peak electric load for the business.

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Potential for Savings Using a Gas Booster Heater in Commercial Dishwashing Applications