Alfa-Laval to Lasko Fan: FAQ on Evaporators, Cooling Towers, Kerosene Heaters, and How to Flush a Hot Water Heater

I didn't plan to become the person people call when heat-transfer questions get weird. It comes with the territory after you've worked around process equipment and made a few expensive mistakes.

Here's the thing that surprised me: an Alfa Laval evaporator, an Alfa Laval cooling tower, a Lasko fan, a kerosene heater, and a home hot water heater all move heat. But nobody explains the differences clearly. I put this FAQ together from the questions I get asked most—including the ones I had to learn the hard way.

Jump to:

• Is it “alfa-laval” or “Alfa Laval”?
• What is an Alfa Laval evaporator, actually?
• Do I need an Alfa Laval cooling tower if I already have heat exchangers?
• Can a Lasko fan replace industrial cooling?
• Can I use a Lasko fan with a kerosene heater?
• How to flush a hot water heater without wrecking it

Is it “alfa-laval” or “Alfa Laval”?

The official name is Alfa Laval, two words and no hyphen. Enough people type “alfa-laval” that it's practically an alternate search spelling, but when you write a purchase order or a spec, use Alfa Laval.

Alfa Laval is a Swedish company that makes heat exchangers, separators, pumps, and related process equipment. If you search online, official material is at alfalaval.com. You may still see the hyphen in old emails and third-party directories. I've seen it both ways. It's one of those details that matters once you're matching model numbers.

What is an Alfa Laval evaporator, actually?

Careful here because “evaporator” means different things in different trades. An HVAC contractor talks about the evaporator coil that absorbs heat indoors. An Alfa Laval evaporator is usually process equipment that concentrates a liquid by removing water or solvent through evaporation.

In a typical setup, the product flows over heated plates or through a falling film under vacuum. Lowering the boiling point protects heat-sensitive liquids. The evaporated vapor is drawn off, and the remaining liquid becomes more concentrated. This type of equipment is common in dairy ingredients, chemicals, ethanol production, and even marine fresh water generation.

If someone says “Alfa Laval evaporator” and expects a small refrigeration coil, that mismatch alone can cause a seriously wrong order. I've watched it happen. Ask whether the duty is concentration or cooling before you ask for a price.

Do I need an Alfa Laval cooling tower if I already have heat exchangers?

They do different jobs. A plate heat exchanger moves heat from one fluid to another without mixing them. If your plant has an Alfa Laval heat exchanger rejecting heat into cooling water, that water now has to give the heat back to the atmosphere. That's the cooling tower's job.

In an open cooling tower, some water evaporates into air, carrying heat away. In a closed-circuit tower, the process fluid stays in a coil while spray water and air remove heat. Both types can work with Alfa Laval equipment. The phrase “Alfa Laval cooling tower” usually describes a complete water-cooling setup rather than a single universal product. The important engineering details are flow rate, entering and leaving water temperatures, and local wet-bulb temperature.

I learned this the expensive way in 2022. I approved a replacement tower with an old flow figure from a process diagram, and I didn't verify the summer wet-bulb design. The tower couldn't hold the required water temperature. The fix cost about $11,000 and delayed startup by nine days. The fan was big enough. The cooling capacity wasn't. You can't see that on a spec sheet unless you ask for it.

Most buyers ask what horsepower the fan motor has. The better question is this: What approach temperature can you guarantee at my design wet-bulb? Approach is the cooled-water temperature minus the wet-bulb temperature. If the vendor doesn't know your design wet-bulb, the quote is just a guess.

Can a Lasko fan replace industrial cooling equipment?

I get this from people trying to cool a workshop, server closet, or small process area on a budget. A Lasko fan is good for making a person feel cooler. It moves air across your skin and speeds up sweat evaporation. It does not lower the air temperature.

An industrial cooling tower removes heat by evaporating water, not just by turning a fan. A portable fan can't do that. Use a Lasko fan for spot cooling if it makes sense, but don't call it an industrial cooling tower substitute. When the equipment needs 80°F water returned to it, a fan pushing 95°F air isn't going to fix the problem.

Can I use a Lasko fan with a kerosene heater?

The safe rule: don't aim the fan directly at the heater. A kerosene heater depends on steady combustion. When a strong stream of air hits the burner, the flame can flicker, soot up, and increase the risk of carbon monoxide instead of producing clean heat.

I did something similar in a small workshop. I pointed a fan at a kerosene heater to push warm air across the room. The flame started flickering, and I realized the airflow was hitting the burner instead of just mixing the room air. I moved the fan so it circulated air in the middle of the space, not directed at the heater. Simple fix, but I learned to respect the combustion zone.

Kerosene heaters also need ventilation and clearance. A fan can't fix an unvented heater in a tight room. If the manual says to keep the heater away from drafts, treat the fan as a draft. That applies no matter which fan brand you use.

How to flush a hot water heater without wrecking it

I know it's called a “hot water heater” even though plumbers like to point out that the water is already hot. I'm using the term because that's how you probably searched for it. Sediment is the reason to do this. It collects at the bottom, makes rumbling sounds, lowers efficiency, and can eventually burn out an electric element or create a hot spot in a gas-fired tank.

Before starting, read your heater's manual. If it says something different, follow the manual. These steps are typical for a standard tank-type heater as of early 2025:

1. Shut off the gas or electricity. Wait until the tank is warm but not hot enough to burn you. Opening a hot water faucet and testing the water is a decent check.
2. Turn off the cold water supply that feeds the tank.
3. Open the nearest hot water faucet. This lets air in so the tank drains instead of vacuum-locking.
4. Connect a garden hose to the drain valve near the bottom and run the other end to a floor drain, driveway, or sump pit. Open the drain valve.
5. Watch the first few gallons. If the water is full of rust chunks or the tank is old, stop and call a plumber. A badly neglected tank can start leaking after sediment is removed. The sediment may have been hiding a weak spot.
6. Once the tank is mostly empty, close the drain valve, open the cold water supply for about 20 to 30 seconds, then close it and drain again. Repeat until the water runs clear. This stirs up bottom sediment better than one long drain.
7. Close the drain valve, remove the hose, and make sure the drain valve is closed tightly.
8. Leave the nearest hot water faucet open and turn the cold water supply back on. When water comes out at a steady flow with no sputtering, the tank is full. Then close the hot water faucet.
9. Turn the gas or electricity back on only after the tank is completely full. Turning it on early can overheat an empty tank, damage the tank, or burn out electric elements.

That last step sounds dramatic, but it's the one I almost skipped during a late-night repair. If I had turned the breaker back on without refilling the tank, it could have cost me a new water heater on top of a long day.

If you live in an area with hard water, check the tank every six months. If the heater is new and you're starting a good habit, once a year is usually enough. Put a reminder on your calendar. Flushing a hot water heater is boring, cheap maintenance. Skipping it is how you end up buying a replacement on the coldest weekend of the year.