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The Article Is About Two Upcoming A/C technologies —  Indirect Evaporative Cooling (IEC) & DeVap Cooling. 

IEC does not increase indoor humidity like traditional Evaporative Coolers (EC) do.  But, just like traditional EC — IEC requires low outdoor humidity.  So, IEC is not suited for humid areas like DFW. 

DeVap uses traditional Evaporative Cooling (EC) — BUT dehumidifies incoming (outdoor air) before it passes through the evaporative cooler. This two-step process makes it able to keep indoor humidity level below 50%.  DeVap cooling doesn’t require low outdoor humidity — making it promising for humid areas like DFW.  

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Al’s also provides full-service plumbing maintenance, repairs, and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Plano, TX; Allen, TX; and Frisco, TX.  We service all homes in southern Collin County, TX and Denton County, TX with no additional travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience.

Conventional Air Conditioners — How They Work

central air conditioner outside unit

Image Source: Shutterstock

Shown:  Central A/C Outdoor Unit (called: “condenser”)

Traditional A/C converts refrigerant back & forth between vapor and liquid.  The outdoor unit’s compressor compresses the refrigerant vapor, then the heat in the refrigerant is removed as it passes through the outdoor unit’s condenser coil.  As the heat is removed, the refrigerant changes from vapor into a liquid — and moves indoors to the indoor cooling coil.

Image Source: Shutterstock

Shown: An Indoor Cooling Coil (called: “evaporator coil) — sits behind the yellow & black device the man is holding.

As the refrigerant passes through the indoor cooling coil (called: evaporator coil) — the refrigerant changes from a liquid into a gas.   When this happens, the gas becomes quite cold — allowing the cold coil to remove heat and humidity from the home’s indoor air (as it passes through the coil).

Note: The indoor cooling-coil is inside the furnace or ductwork, and can’t be seen without removing a panel.

Large amounts of electricity are required to cycle refrigerant.  As the population grows, and the use of A/C increases — traditional A/C is causing increasing strain on the interconnected power-grids serving the U.S, and adds to global warming.   Additionally, some refrigerant gets leaked into the atmosphere — harming the environment.

Today, some forward thinkers have looked backward into time — and created Indirect Evaporative Cooling (IEC).  It’s a better version of traditional Evaporative / swamp coolers (EC) — that uses a heat-exchange unit that keeps evaporating water separate from the air coming into the house.  This eliminates the added humidity with EC.  But, just like EC, IEC requires low outdoor humidity to work.  This makes both EC and IEC not suited for humid areas like DFW.

Traditional Evaporative (swamp) Coolers  (EC) — How They Work

Traditional Evaporative Coolers (also called swamp coolers) bring outdoor air over water-saturated pads and into the house.  As the air passes through, water evaporates into it.  When water evaporates, it takes heat with it (this is why we feel cooler when we sweat).  Evaporative Coolers are only effective in areas with low outdoor humidity, such as the southwestern U.S.  The lower the outdoor humidity, the better EC coolers work — because it’s able to evaporate more water (thus removing more heat).

Traditional Evaporative Coolers (EC) Can’t Work In Humid Areas Like DFW: 

  • At 30% outdoor humidity — traditional evaporative / swamp coolers (EC) can lower temperatures around -20 degrees.
  • At 50% outdoor humidity — EC can drop temperatures only -10 degrees.
  • At 75% outdoor humidity — EC can’t work.  Because the cooler can’t evaporate enough water to remove sufficient heat from incoming air.
  • Above 25% outdoor humidity — EC adds too much moisture into the indoor air (details just below).

For an evaporative / swamp cooler (EC) to lower the temperature -20 degrees — it must increase the indoor humidity by 25%.  Ideal indoor humidity level is up to 50%.  So, the outdoor humidity level should not exceed 25% for EC to sufficiently cool the home —  and without causing indoor humidity to become too high.

  • DFW’s average July humidity = 65%.
  • Las Vegas average July humidity = 24%.
  • An Evaporative Cooler works in Las Vegas — but not DFW, due to outdoor humidity level.

evaporative or swamp cooler

home with a swamp cooler or evaporative cooler

Image Source: ShutterStock

Shown: Evaporative Coolers (also called: “Swamp Cooler”)

 

Indirect Evaporative Coolers (IEC) — How They’re Betterer Than Traditional Evaporative Coolers (EC)

IEC Does Not Add Humidity To Incoming (outdoor) Air Like Traditional Evaporative Coolers (EC) Do.

IEC cooling systems have a Heat-Exchange Unit that keeps evaporating water separate from the home’s incoming (outdoor) air.  Until recently, IEC cooling systems were difficult to make due to the complicated heat-exchange unit.  This made them expensive, and their performance hard to optimize.  Until recently, IEC cooling was mostly a theory.

Jack Alvarenga, M.S. and Jonathan Grinham, D.Des. created a technology called: “Cold SNAP”  Indirect Evaporative Cooling (IEC).   IEC requires little electricity and doesn’t use chemical refrigerants that damage the environment (if leaked) like traditional A/C requires.  BUT, just like traditional Evaporative Cools (EC) — Indirect Evaporative Cooling (IEC) requires low outdoor humidity.  This makes it not suited to humid areas like DFW.   Just below, we discuss DeVap cooling which does not require low outdoor humidity — making it promising for humid areas like DFW.

The IEC “Cold-Snap” Difference — Indirect Evaporative Cooling

Cold-SNAP Indirect Evaporative Cooling uses a heat-exchange unit made of ceramic.  With IEC’s Heat-Exchange Unit — incoming air does not come into contact with water like with traditional Evaporative Coolers.  This allows IEC to cool without adding humidity.  Evaporative / swamp coolers (EC) — add +25% to indoor humidity.

The Heat-Exchange unit’s ceramic surface has a coating applied (called: “hydrophobic coating”).  The surface-coating makes ceramic very water-repellent (uncoated ceramic absorbs water).  This new coating was developed by Joanna Aizenberg, Ph.D.

IEC Coolers Only Work In Areas With Low Outdoor Humidity.   IEC Won’t Work In Humid Areas Like DFW

  • IEC coolers can drop the temp. a maximum of -15 — and the outdoor humidity must be quite low to achieve that.
  • Traditional evaporative coolers (EC) can drop the temperature up to -20 degrees.  With 30% outdoor humidity (like Las Vegas, NV has).
  • Conventional A/C can drops the temp up to -24 degrees — and humidity doesn’t affect performance.
  • IEC coolers have limited (if any) dehumidifying ability — like A/C does.
  • IEC’s benefit (over traditional Evaporative Cooling /  EC) —  is that it doesn’t add humidity to incoming air — like EC does.
  • IEC uses up to -80% less energy than conventional A/C.
  • But, IEC still requires low outdoor humidity — to evaporate enough water to effectively cool the Heat-Exchange Unit.
  • For this reason — IEC cooling is not suitable for humid areas like DFW.

 

DeVap (Desiccant-Enhanced eVaporative) Cooling

Dehumidifies Incoming (outdoor) Air

DeVap Cooling Uses A Traditional Evaporative Cooler (EC) — But First Dehumidifies Incoming (outdoor) Air Before It Enters The EC.

  • When water evaporates — it takes heat with it.  This is the entire basis of Evaporative Cooling (EC).
  • In humid areas like DFW — traditional EC won’t work because the outdoor air is too humid.
  • In humid areas — traditional EC would add too much humidity to incoming air (+25%).  This would make the house would feel “muggy”.
  • With DeVap’s dehumidifying step — the EC cooling step is not impacted by high outdoor humidity.
  • With DeVap’s dehumidifying step — This Cooling Technology Shows Promise For Humid Area Like DFW.

  • Because DeVap uses some fresh air from outdoors — it creates a healthier indoor environment than conventional A/C (which uses 100% recycled air).
  • DeVap uses a separate energy source (such as natural gas or solar) to power the dehumidifying step.
  • DeVap’s actual savings depends on how much dehumidification is required.
  • DeVap uses up to -30% less energy (with gas dehumidifying) than conventional A/C.
  • DeVap uses up to -80% less energy (with solar dehumidifying) than conventional A/C.

With solar assistance, the heat generated is used directly to dry the dehumidifying desiccant (salt water).  This makes the solar-assistance much more efficient than conventional solar panels — which convert sunlight into electricity.

  • The compressor in central A/C’s outdoor unit is what uses so much electricity.
  • An older,  SEER-10,  3-ton / 36,000 BTU Central A/C (size for a 2,000 square foot DFW home) — uses 3,600 watts per hour.
  • A SEER-14 A/C (today’s minimum SEER in DFW) uses 2,575 watts. **

Note: Divide the BTU’s by the SEER to determine how many watts a central a/c uses.

  • A DeVap Cooler dehumidifies air to less than 20% relative humidity before the air enters the evaporative cooler. ***
  • With 20% relative humidity incoming air — traditional EC’s output air is -21 degrees lower (conventional A/C output air is up to -24 degrees cooler).
  • The evaporative cooler (EC) will raise the humidity of output air (entering the home) by +25% — so total humidity stays below 50%.  Ideal indoor humidity is up to 50%.

*** Source: https://www.nrel.gov/docs/fy13osti/54087.pdf

See A Photo Of The Prototype DeVaporative Cooler Below

Image Source: Embedded Video Link

Click On The Arrow In The Center Of The Image For A Short YouTube Video Describing DeVap Coolers

Click On This Link To Read More About DeVap Cooling From The Inventors:  DeVap Cooling Article

DeVaporative Coolers — In Laymen’s Terms

Desicccant packets

Shown: Silica Gel Is A Desiccant (Removes & Holds Humidity)

Image Source: Shutterstock

“Desiccant” Is The Technical Name For A Substance That Removes & Holds Moisture

  • You often see Silica Packets inside product packages.   Silica is a desiccant.
  • If a Silica packet is included — it’s there to eliminate moisture that could affect the product.
  • DeVaps’s desiccant is salt water.

DeVap Cooler Operating Costs — As Compared To Conventional A/C

  • Once the salt-water desiccant removes the humidity — it must then be heated to remove the moisture within it.
  • A DeVap System uses natural gas or solar heat to remove the humidity.
  • A 3-ton / 36,000 BTU DEVap Cooler uses a 30,000 BTU gax boiler to heat the salt water.
  • As compared, a 50-gal. water heater uses 36,000 BTU.
  • A therm of natural gas provides 105,000 BTU of heat.  Running constantly, the Desiccant Regenerator uses 30,000 BTU per hour — or 720,000 BTU’s of natural gas per day.
  • DeVap uses 7 therms of natural gas per day (running continuously).  A therm costs 16.5 cents X 7 therms per day = $1.15 Daily gas cost. 
  • The blower fan motor uses 500 watts per hour (running continuously).  It uses 12,000 watts, or 12 kWh.   Daily electricity cost = $1.55  (if running continuously).

Daily DeVap Cooler Operating Costs = $2.75 (if running constantly)

  • A 3-ton / 36,000 BTU Conventional A/C (SEER-14 –minimum allowed in DFW) uses 2,575 watts per hour.
  • This A/C would use 62 kWh (kilowatt hours) in a day – if running constantly.   1 kWh costs 12.8 cents X 62 kWh = $7.95

Daily Conventional A/C (3-Ton, SEER-14) Operating Costs = $7.95 (if running constantly)

Notes:

  • The more humid outdoor air is — the more energy is needed to dehumidify incoming air in a DeVap Cooler.  This increases operating costs.
  • Our numbers shown are for the dehumidifier / regenerator running continuously.
  • If outdoor humidity drops below 40%, the dehumidifier can be turned off — notably reducing DeVap’s operating costs.
  • Summer DFW outdoor humidity below 40% would be rare.

** https://psmag.com/environment/air-conditioning-using-90-percent-less-power-20071

*** https://www.nyseg.com/UsageAndSafety/usingenergywisely/homeenergyuse/NaturalGasAppliances.html

Additional Differences Between DeVap Cooler & Central A/C System

  • DEVap Cooler does not have a large outdoor unit.
  • DeVap has a much smaller “Desiccant Regenerator” that dries the salt water desiccant.   The regenerator can be inside or outdoors.
  • Conventional A/C utilizes a complicated process to convert refrigerant back and forth between liquid and gas.
  • Converting and moving refrigerant with an electric compressor requires a lot of electricity.
  • DeVap’s refrigerant is salt water.
  • DeVap uses a natural way to remove heat — with evaporating water.
  • DeVap electricity use is much lower.
  • DeVap does not require a chemical refrigerant. 
  • DeVap uses salt-water as its refrigerant.
  • The American Society of Heating, Refrigerating & Air-Conditioning Engineers (ASHRAE) recognizes water as “Refrigerant R-718”.
  • Older A/C used Fron as its refrigerant.
  • Newer A/C uses R410 as its refrigerant.
  • R410 refrigerant won’t damage the Ozone Layer (if leaked).
  • But, R410 contributes slightly more to global warming (if leaked) than Freon.
  • R410 refrigerant’s global warming potential = 2000 — but won’t damage the ozone layer.
  • R-22 / Freon’s global warming potential = 1810.  It’s a little lower than R410 — but damages the ozone layer.
  • “Greenhouse-Gases” absorb and trap the sun’s heat.
  • Global warming potential (GWP) is a measure of how much heat becomes trapped in the atmosphere.
  • DeVap cooling (with solar dehumidifying) — does not add to global warming.

SUMMARY:

At present, DeVap Coolers are still in prototype.   In time, residential units may become available — and would create large savings versus conventional air conditioning.  Actual savings is determined by how much humidity is in the air.

DeVap Cooling incorporates a conventional Evaporative Cooler / EC (as known as a swamp cooler).  EC cool the air by drawing it through a water-filled mesh.  As the air passes through the mesh, evaporating water cools the air (just like evaporating sweat cools our skin).   But traditional swamp coolers are only useful in areas with low humidity such as the southwestern U.S.

DeVap Coolers include a dehumidifier.  The air is dehumidified first — then passed through the evaporative cooler.  The lower the humidity of the incoming air, the better an Evaporative Cooler can cool.  A DeVap Cooler is able to perform well in climates with high humidity.

The higher the humidity, the harder a DeVap system must work to dehumidify the incoming air.  While high humidity increases operating costs,  DeVap coolers would still operate much cheaper than conventional A/C.   As presented in this article, a DeVap Cooler in DFW (with gas-powered dehumidifying running continuously) cools for a little over 1/3 the cost of conventional A/C.

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The article was about two new A/C technologies —  Indirect Evaporative Cooling (IEC) & DeVap Cooling.   IEC does not add humidity to incoming (outside) air (like traditional Evaporative Coolers (EC) do.  But, IEC still requires low outdoor humidity — so it’s not suited for humid areas like DFW.

DeVap uses traditional Evaporative Cooling (EC) — AND dehumidifies incoming (outdoor air).  DeVap cooling doesn’t require low outdoor humidity — making it promising for humid areas like DFW.

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Al’s also provides full-service plumbing maintenance, repairs, and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s is near your home in Richardson, TX; Garland, TX; and northeast Dalla, TX.  We service all homes in southern Collin County, TX and Denton County, TX with no additional travel charges.