Factors Affecting Feasibility
Evaluating the feasibility of waste heat recovery requires characterizing the waste heat source and the stream to which the heat will be transferred. Important waste stream parameters that must be determined include:
- Heat quantity. A large and constant volume of heat is ideal, although there are options for smaller heat quantities.
- Heat temperature/quality. A high-temperature heat source can yield greater outputs, although the temperatures can also affect what materials are used in the equipment design of heat exchangers and recovery systems.
- Composition. A heat source free of corrosives or particulates is best; otherwise, more expensive heat exchangers and maintenance increase the costs.
- Minimum allowed temperature. Too cool a temperature can cause the water vapor in exhaust gas to condense and deposit corrosive substances on the heat exchanger.
- Operating schedules, availability, and other logistics. For example, it is important that the schedule of the heat source match the schedule of the heat load. It is also important that the recovery not interfere with the industrial process that is the source of the waste heat.
- Location. When generating electricity, a close proximity to the electric grid (and ideally a transmission line) is preferable.
- Economic incentives. Some states offer tax credits, grants, and/or eligibility in renewable portfolio standards, any of which help the economic feasibility.
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