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Renewable Heating And Cooling

Renewable Industrial Process Heat

About Industrial Process Heat

The United States’ industrial sector uses heat for a wide variety of applications, including washing, cooking, sterilizing, drying, preheating of boiler feed water, process heating, and much more. Altogether, the industrial sector uses and estimated 24 quadrillion Btu, or roughly one-third of the nation’s delivered energy supply.1 Process heating applications alone account for approximately 36 percent of total delivered energy consumption within the manufacturing sector (a subset of the industrial sector).2 The vast size and scale of industrial heating energy use represents a unique opportunity for renewable resources.

According to a study of industrial heating in European countries, 30 percent of industrial heating applications require heat below 212°F, another 27 percent can be met with heat between 212 and 750°F, and the remaining 43 percent require heat above 750°F.3 Most existing renewable heating technologies can easily and cost-effectively supply heat within the lowest indicated temperature range. Often, the most valuable role that renewable heating technologies can play in industrial applications is to provide “pre-heating” before an existing conventional energy source is used. Major considerations for industrial renewable heating applications include cost, resource intermittency, and process integration and storage options.

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How Renewable Industrial Process Heat Works

Solar, geothermal, or biomass sources can provide heat to support industrial processes that serve water- or air-heating end uses. As described above, more than half of industrial heating is met through temperatures below 750°F, and some industries (agriculture, cooking) have much lower temperature needs. Many renewable heating resources can easily meet the lower temperature requirements. Even if renewable sources cannot support the entire heating load, they can still provide pre-heating to supplement a conventional heating process. Because it takes a relatively large amount of energy to raise the temperature of water (compared with heating air, for example), even a modest amount of pre-heating can reduce a facility’s dependence on fossil fuels—and save money in the process.

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Compatible Renewable Technologies

Flat-plate solar collectors and ground source heat pumps can support industrial processes requiring warm to hot water, such as pressurization or pre-heating water. Many agricultural processes also require gentle warming. For example, flat-plate solar collectors and ground source heat pumps can help to warm soil or warm water for fish farming to about 100°F.

Chemical processing, kilning, drying, curing, sterilization, and distillation activities requiring higher temperatures can use evacuated tube solar collectors, direct use geothermal water, or biomass furnaces. Concentrating solar thermal technologies and deep geothermal wells can support the highest-temperature applications, such as fuel production, that require pressurized, superheated water or steam above 480°F.

Agricultural and industrial facilities often take advantage of co-location and cogeneration. Waste agricultural products such as rice and corn husks can potentially serve as effective biomass fuels. Similarly, waste heat from a high-temperature industrial process can possibly support another process requiring a lower temperature.

The interactive diagram below shows how industrial processes align with selected renewable technologies. You can click any of the technologies to go to a new page with more detailed information.

Renewable Industrial Process Heat Technologies and Applications

Understanding the Diagram

The diagram above shows technologies and industrial process applications in terms of the approximate “working temperature” range, which is the required temperature of the heat transfer fluid within the renewable heating system. The working temperature is not necessarily the same as the final temperature of the end product (in this case, the final temperature of the air or water that is being heated).

The diagram above shows approximate working temperature ranges. The exact working temperature requirements for a particular system will depend on factors such as system type, size, and location. The working temperature that a particular renewable technology can supply will also depend on site-specific factors. For example, the amount of heat that a solar collector system can supply will depend on how much sunlight it receives, and at what angle.

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U.S. Department of Energy, Energy Information Administration. 2014. Annual Energy Outlook 2014: Industrial Sector Key Indicators and Consumption.
U.S. Department of Energy, Energy Information Administration. 2006. Best Practices: Process Heating (PDF)
(2 pp, 428 K, About PDF).
International Energy Agency, Solar Heating and Cooling Program. 2008. Potential for Solar Heat in Industrial Processes. Exit