- Created on Friday, 02 July 2004 16:31
- Written by Lee R. "Skip" Kemberling, CEO, Kemco Systems, Inc
With projected costs of $50.00 per barrel of oil or $10.00 per therm for natural gas, it is an absolute necessity for laundries to implement thermal energy conservation. But what can you expect to save by installing energy conservation systems? For each of the products listed below, you'll find the percentage of total energy conservation.
|Wastewater Heat Reclaimer||50|
|Direct Contact Water Heater||30|
|Vent condenser/steam recovery||12-15|
Keep in mind, it's important to consider various factors when choosing an optimum energy conservation system for your plant. Those factors include, plant mix, geographical location, projected fuel cost, chemical costs, number of shifts, applicable hours of operation, and environmental laws or mandates. So what do all of the above systems do? And how can they help you conserve?
WASTEWATER HEAT RECOVERY:
Wastewater heat recovery systems use the heat in the dirty water from the previous operations to preheat the incoming cold water for the next operation. Heat reclaimers preheat the cold (40°F to 65°F) incoming water to within several °F of the wastewater temperature (110°F to 135°F) providing one-half of the heat needed for hot water.
Laundry wastewater contains lint, wine corks, buttons, coins, and other suspended solids which quickly plug any heat exchanger not proven in laundry application. If all or part of the heat reclaimer plugs, the wastewater cannot pass and no heat transfer takes place. Wastewater filters before non-continuous tube type heat reclaimers, reduce, but do not eliminate, plugging of the non-continuous tube exchangers. Continuous tube type heat reclaimers equipped with automatic backflush cleaning are guaranteed not to plug or stop up, are recommended, and give continuous clean results without manual cleaning.
BOILER STACK ECONOMIZER:
Boiler Stack Economizers use the heat remaining in boiler exhaust gases to reduce fuel requirement by preheating the water used in the washing. Recent increases in fuel costs have resulted in a renewed emphasis on the flue gas heat recovery. Direct contact condensing technology has overcome technological barriers, such as cold end corrosion and tubular scaling and fouling, resulting in a 200 to 300 percent increase in heat recovery increased efficiency, and significantly improved return on investment (ROI's). Today ROI's of 200 percent per year occur and ROI's of 50 percent per year are to be expected.
DIRECT CONTACT WATER HEATER:
Direct Contact Water Heaters use a gas burner which fires directly into the water. As it passes the combustion gases in counterflow, the water is heated and falls to the bottom of the tank where it is pumped to process. The temperature of exhaust gas are reduced to equal or less than the ambient temperature, thus eliminating any stack losses. Evaporation heat of combustion is captured and used. This system easily saves 30 percent of gas used to make hot water compared to a boiler steam heat exchanger water heater. The saving results by eliminating the losses of a boiler steam heat exchanger system, such as hot stack gasses, blowdown heat, radiation and convection losses of the boiler, steam pipe, condensate return pipe and tank and flash steam.
FLASH STEAM RECOVERY SYSTEM:
Each pound of condensate gives up approximately 144 BTU in the form of steam before it becomes water at 212ºF (100ºC). This surplus of 144 BTU becomes steam (flashes) and escapes from the vent of the condensate receiver. This represents 11.8 percent of the fuel consumed. This fuel is used to create the steam which is not used. All of this energy can be recovered with a Flash Steam Recovery Unit.
Quick Rinse - News From Around The World
Fire in Jail Laundry
DURHAM, N.C. — A fire in the laundry room at a County Jail in Durham damaged goods but required no evacuation. The fire, which originated in a dryer, damaged hundreds of uniforms. In addition to the lost goods, the jail’s laundry sustained water and smoke damage. The fire was extinguished by the sprinkler system that had been activated.