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Published: July 29, 2009
Utilities at any industrial manufacturing center are a direct cost and constant strain on profitability. Three of the most commonly used utilities are steam, hot water, and chilled water. Steam is usually generated by a boiler (electric, natural gas, or fuel oil) and chilled water is generated by a electric chiller utilizing a common refrigeration cycle. Hot water is then typically generated by using the steam to heat water in a heat exchanger.
If you're plant uses hot water and chillers, you'll be pleased to learn that there is a commercially available, proven technology to dramatically lower your utility costs associated with these utilities with a payback averaging 1 1/2 to 2 years.
The Thermally Powered Heat Pump / Chiller
The best summary of the technology is that you input ambient water, low pressure steam (50 psi or higher), and minimal electricity for pumping. You get water delivered at a minimum temperature of 110 °F (maximum temperature of 160 °F) and chilled water as low at 34 °F. All the while, you're saving about 30% of the cost of producing hot water and 90% of the energy needed to produce chilled water.
So, how does it work? The ThermoSorber uses an old thermal cycle fluid (ammonia) in a new way. By utilizing a rectifier and a generator together along with a condenser, absorber, and an evaporator, each "unit" of steam is used to produce 1 + 0.60 units of hot water and 0.60 units of chilled water. Essentially, the ThermoSorber produces hot water at 156% efficiency. Chilled water is produced as a by-product of the heat pumping action without any further energy inputs outside of pumping ammonia/water solution. The cycle begins with a solution of ammonia and water which is pressurized and heated to generate ammonia gas and desorbed liquid. The gas is condensed, releases heat, and is then expanded to low pressure to produce a vapor and cooling. The resulting ammonia vapor is absorbed back into the desorbed liquid to produce a solution and additional heating. Now, the solution is pumped back to the generator. The ThermoSorber supplements that cycle with proprietary heat and mass exchangers.
Here are some example inputs and outputs from an installation at a large poultry processing plant. The ThermoSorber delivers 350 kW of chilling capacity and 930 kW of hot water capacity from 580 kW of steam. The chilled water is delivered at 41 °F and the hot water is at 137 °F.
The ThermoSorber shown in Figure 5 was installed at a meat packing plant in Green Bay, Wisconsin. It produces 10.5 million Btu/h of 145 °F hot water plus 300 tons (1000 kW) of 34 °F chilled water. The feed steam rate is 7,500 lb/h at 100 psig.
100 Ton Heat Pump/Chiller, Livingston, CA
This installation provides 100 tons of chilling and 3.2 million Btu/h of hot water from a steam input of 2 million Btu/h (about 2,000 lb/h). This $200,000 installation provides utility savings of at least $120,000 each year.
160 Ton Heat-Actuated Chiller, Blythe, CA
Part of an 830 kWe distributed energy project, this installation uses exhaust and jacket heat from natural gas engines to produce 160 tons of 26 °F chilled water. This system reduced the customer's electrical costs by 20% and boosts the effective efficiency of converting natural gas to electric to above 40%.
60 Ton Solar Chiller, Douglas, AZ
A solar collector supplies 210 °F heat to this system. The system returns 60 tons of 44 °F chilled water to Cochise Community College. The COP is 0.75.
If you'd like to learn more about the ThermoSorber technology, please complete the form at the top of this page.
By: Christopher Haslego, Owner and Chief Webmaster (read the author's Profile)