Sizing of the extractor and evaporative cooler in dry cleaning plants
Almost all dry cleaners use evaporative coolers, or swamp coolers as some call them, in their plant or laundry area. Using refrigerated air conditioning would be too expensive for them. Your steam boilers are putting out hundreds of thousands of BTUs of heat into the work area. Eliminating so much heat using air conditioning would cost thousands of dollars a month. Because of this, the dry cleaner’s work area should have an exhaust fan that is capable of performing a full air exchange approximately every 1 1/2 minutes. Let me give you an example to help you determine the correct exhaust fan size for your cleaner.
Let’s say you rent a space in a shopping center that is 25 feet wide by 80 feet deep. The total square footage of this rental space is 2,000 square feet. foot The front selling area is typically heated and air-conditioned. Next, remove from the 2,000 square feet. foot your sales area 25 feet wide by 15 feet deep that totals 375 square feet. ft This leaves you with 1,625sq. foot The boiler room is 10 feet by 10 feet (100 square feet) and the bathroom is 6 feet by 6 feet (36 square feet) which adds up to another 136 square feet. foot generally does not figure in the cooled area. This gives you a final total of 1,489 sq. foot of floor space in work area for ventilation and cooling. To get the cubic feet of the work area, you need to measure from the floor to the roof deck. I say roof covering because I never recommend installing a roof in the work area. This only keeps the heat lower in the room and makes the work area much warmer. Multiply the 1,489 squares. foot by the 15 feet from the floor to the roof deck and you get a total of 22,335 cubic feet of area to extract. Divide 22,335 by 1 ½ (the number of minutes per air change) and get the total number of cubic feet of air to remove each minute, or the CFM. Under these conditions, you would install an exhaust fan rated at approximately 15,000 CFM. The most common exhaust fans used in dry cleaners are Grainger fans. There are Grainger stores in most major cities in the United States, making it convenient to purchase fans and replacement parts. I have bought extractors from Grainger for years. I learned a way that any Grainger customer, even if you’ve never bought from them before, can get a 10% discount on their fans. If you email me, I’ll let you know how you can get the discount at any Grainger store in the country.
Next, you must compensate for the exhausted air with an Evaporative Cooler. These work very well in dry climate areas. But even in more humid areas they give some cooling. You might only get a 10 degree drop in temperature in a humid area, but on a 95 degree day a slight 85 degree air breeze can feel good while working on a hot press. In a dry cleaning plant, you will usually find them using a large commercial evaporative cooler. For the work area I sized above, you would need to install a 15,000 CFM cooler. Keep in mind that when you look at refrigerators, they usually give the CFM ratings outdoors. Since you will likely have a duct system that cools the work area, there is static pressure or restriction in the airflow from the cooler. If you use a 15,000 to 16,000 CFM evaporative cooler you will probably have a good match with the 15,000 CFM exhaust fan. Static pressure from the ducts will generally lower the CFM rating by a couple thousand CFMs. The reason this combination is good is because you want a small amount of negative pressure in the work area – in other words, a little more air coming out of the room than is being supplied into the room. The most common evaporative cooler used in dry cleaning work areas is the Champion 14/21 SD or the Essick 14/21 SD. These are the most common because they are the cheapest models sold. If you are willing to spend a little more money, I recommend that you go to a cooler that will last you much longer. The Champion AS150 or Champion AS15012 are better built and more durable coolers. If you want a better explanation of the reasons why they are better Coolers, you can type these Coolers into a search engine and find articles written about them.
I know there is a lot of technical information that would be boring to many people, but if you want to cool down a dry cleaning plant, I recommend using this information. I have installed exhaust and cooling systems at Cleaners for decades in the Dallas / Fort Worth, Texas area. These formulas and equipment have worked very well. I hope these tips I have learned will help others in the future.