4 in 1 A.C. humidity and cooling

Speed of green said:

I dont know anything about the unit you describe, however i will add my personal opinion on something that i consider close to this topic.

I am a simple person and i like redundancy, combo EC/PPM/PH meters, Master grow room room/greenhouse controllers, things of this combinable nature are incredible ideas on paper and in some instances can work flawlessly. however in my experience these items have lead to expensive dead ends that resulted in me buying the right products the second time.

Again im not knocking your combination AC, just saying do your homework.

Some mechanical combo items are an incredible hit and go together well, like the can opener & bottle opener.

Hope this helps.

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queequeg152 said:

nobody makes a small combined ac/dehuy far as i know.

the funny thing is... there is actually a market for these devices, as more and more folks are building progressivly more efficient homes that are vastly more air tight... as this trend continues the required size of ac units has been shrinking to the point where, "technically" many new homes only need something like 12kbtuh to cool like 1200 square feet. in many cases though, heat pump capacity is dictating the size of your unit however.

when you build an efficient home, the need for dehumidification becomes more urgent as you are just not running your ac unit enough to do the work of dehumidification.


what you have here is known as marketing bullshit. its-in all likelyhood, just a portable AC unit with an electric heater.

if you need and AC only, then fine. buy it. but dont expect it to dehumidify as well as a standalone dehuy.

the problem with combining all of this shit into one air handling unit is you need multiple coils, solenoids and damper actuators... it just costs alot, and the complexity means more servicing.

this technolagy has existed for a long time in large scale commercial units... its existed for decades even. but shrinking it down to a portable ac unit thats cheap enough to compete with two standalone units? its basically impossible far as i know.

at a MINIMUM you need an additional coil to make this shit work well... you basically use a valve to bypass hot refrigerant from the compressor discharge away from the condensing coil and back into the air handler UPSTREAM of the evaporator to push the supply air temp higher than indoor ambient such that you can extract vastly more water vapor(dehumidifier 101).

in reality though, they dont even use the same cooling evaporator in many cases ... they have a sepearate reheat coil AND a separate dehuy coil operating in a parallel air stream. 2 seperate coils, 2 valves etc, at a minimum.

the parallel air stream volume is controled with opposed blade dampers( spendy) on variable input actuators( less spendy).

the latter scheme gives you better control of your dehumidification, and the dedicated dehumidification coil means you can use a different coil depth size and fin spacing (without increasing static pressure at your cooling evaporator) to increase the residence time and improve dehumidification fairly dramatically.

in reality though, there are very few instances where you need such a system to control humidity, but they do exist. 99% of the time a properly sized enthalapy wheel at the RTU does the job perfectly fine without alot of excessive reheat. in larger chiller plants you can control air volume and water temp to control humidity to some extent.

again though, the units you are talking about are bullshit marketing wank.

what they are probably doing is reheating the air upstream of the cooling evaporator with an electric heat strip. this WILL increase the units dehumidification, but at the expense of lots of electricity.

its possible they have some sort of built in damper that actually diverts air from the condenser coil into the evaporator... but i seriously doubt they bothered to engineer anything like that. even if they did... you still have the problem of trying to dehumidify with a coil designed for sensible cooling and only moderate dehumidification. it just does not work well enough.

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