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Refrigeration And Energy Savings
With energy consumption at it’s highest levels, Cooling Technology continues to provide innovative process cooling solutions that improve our customer’s bottom line and allows them to take advantage of electric utilities rebates toward the purchase of high efficiency equipment.
METAL FINISHER IN VIRGINA PROVIDED A COST EFFECTIVE COOLING SOLUTION
The customer is a metal processor that has several different type II and type III plating baths and required a chiller that would meet several different load and temperature requirements.
Cooling Technology solution was a model ECR-40P evaporative condensed chiller and heat exchanger/pump skids to be conveniently located next to the baths and transfer the heat from the sulphuric solution to the chilled water.
We utilized Titanium plates in the heat exchanger, along with acid pump, modulating valves and fully wired and mounted electrical control panel.
The chiller used two compressors for redundancy and energy savings at part load conditions. The evaporative-condenser allows the chiller to operate at lower condensing temperatures than a comparable air-condensed chiller and thus is more energy efficient.
We also used an efficient brazed plate evaporator that uses less refrigerant and permitted closer approach temperatures for energy savings.
As a result, the customer’s electrical utility offered them a rebate for buying premium efficiency equipment.
Over a 10-year period, the customer will save over $33,000 in electricity- and this does not even include demand charges, which can account for 40% of a typical utility bill:
40 ton Air-Condensed Chiller
62.4kW x 2,160hrs x $0.06kWhr = $8,087 year
40 ton Evaporative-Condensed Chiller
36.8kW x 2,160hrs x $0.06kWhr = $4,769 year
NOTES
1) Electric utility charges 6 cents/kWh
2) Chiller usage: 12hrs/day, 6 days/wk, 30 wks/yr
3) 95°F ambient, 74°F wet bulb
- Other advantages of the system included:
- Lower kW draw reduced the utility demand charges
- Lower amp draw reduced component and wiring sizes, resulting in lower installed costs.
- Lower compressor head pressure than air-cooled systems increases compressor life.
- Factory prefabrication reduced expensive field labor and installation costs
PLASTIC PROCESSOR IN OHIO SAVES THOUSANDS OF DOLLARS PER YEAR
A major injection molding processor used an inexpensive and creative source for their process cooling needs: ground water.
For years, well water had been the source for hydraulic oil and mold cooling and their water usage was approximately 1-2 million gallons per day for their 24 hour a day operation.
Their innovative water use had problems due to the poor quality of the ground water. While water is available year-round at a constant temperature of 53°F, the water was so heavy with minerals that it had fouled up the molds and heat exchangers. The molds constantly broke down or caused long cooling cycles due to the resulting inefficient heat transfer.
The common solution of chemical treatment was unacceptable as water was used only once before returning to the ground.
Cooling Technology was asked to solve this problem. We recommended an inexpensive and efficiently effective solution: a “closed loop” cooling system where the process equipment was separated from the well water by use of a stainless steel plate and frame heat exchanger.
After passing through the heat exchanger, the now-cooled process water is stored in a 750-gallon reservoir and circulated through the molds. This system was constructed to flow at a rate of 376 gpm and provides virtually clean process water at a consistent temperature of 56°F to the molds.
By itself, this may not seem remarkable until we look at an equivalent traditional chilled water system: The same task would have required 156 tons of chiller refrigeration.
Assuming a water-cooled chilled water system with two 75-ton circuits, the traditional refrigeration system would require 178kW of power at 460 volts.
- Two 75-hp compressor motors
- One 150-ton tower cell (7½ hp fan motor)
- One 15 hp tower water pump
With electricity costing the customer $0.07 per kW hour, the annual cost of operating a chilled water system would have been $28,836 (12 hours per day, 6 days a week, 30 weeks per year).
The new equipment that Cooling Technology provided paid for itself within the first year of its operation without considering the maintenance cost savings.
AIR-COOLED FLUID COOLERS SUPPLIMENT PROCESS COOLING AND BUILDING HEAT
In the northern region of the United States, the cooler weather for nearly six months of the year provides natural conditions for low cost process cooling water by using a air-cooled fluid cooler.
Air-cooled fluid coolers can be incorporated into a cooling system in two ways. The first is for the fluid cooler to remove the majority of the process heat so the chiller provides supplementalheat removal as dictated by the process. Another method is to completely replace the chiller’s function when ambient conditions allow.
Cooling Technology’s chiller micro-controller has the flexibility to support either system and provide automatic operation. A sensor monitors ambient temperature and, when conditions are met, the system turns on the fluid cooler fans, operates motor actuated valves to redirect the process water through the fluid cooler and then turn the chiller off.
By either method, significant energy savings can be realized. Consider a facility with a 50 ton process load located in an area that experience temperatures below 30°F for three months a year. Note, too, that plants often operate 24 hour a day, seven days a week.
By switching from energy consuming refrigeration systems to fluid cooling, a savings of over $10,000 can be realized. The more days below 30°F, the more savings that can be obtained.
When less expensive air-cooled fluid coolers are supplemented by a central chiller system, the integrity of a closed loop water chilled environment is preserved.
Also, the fluid cooler can be located inside a building to recover process heat to supplement the building’s heating system.
In addition, fluid coolers can be used with an evaporative cooling tower system before the water is pumped outside to a cooling tower.
Heat from a 150-ton evaporative cooling tower load, recovered at 75% efficiency factor, will pump 1,687,500 BTUs per hour. This is equivalent to 16-87 therms, or a recovery of $6.75 per hour in fuel (i.e., natural gas) savings. If that’s not impressive, consider a six month heating season, 24 hours per day, seven days a week: the translation is $29,484.00 per year!
In Summary
On your next cooling project, challenge us by asking for efficient and economical solutions for your process cooling needs that will enhance your overall productivity and profitability.
Other “energy saving” solutions we offer include:
- Variable speed motors on process pumps, cooling tower or fluid cooler fans
- Chillers that use multiple compressors to match part load conditions
- Micro-processor controllers that keep chillers running at optimal levels and allows integration into building management systems
- Air-cooled chillers with centrifugal blowers to supplement building heating systems
- Compact and efficient brazed plate heat exchangers that needs less refrigerant and permits the use of closer approach temperatures for energy savings
- Use of highly efficient scroll and screw compressors
- Central chillers with heat recovery units designed to heat domestic hot water up to 140F by capturing rejected heat