Engineering Air Conditioner's with Computerized Digital Readouts for Efficiency Operation Verification

with Darrell Udelhoven
It is shameful that we do not have not only computerized digital readout operational BTU/hr verification, but also computerized operation of all air conditioning and refrigeration equipment.

This would be so easy to do that it is ridiculous that it was not done a decade ago. We have had operational formulas for decades that could easily be incorporated into computer digital readouts, as well as, total-computerized control of both the indoor blower and outdoor condenser systems.

The indoor computer would sense the dry bulb air temperature and the wet bulb temperature (or humidity) and the temperature drop split, along with the blower CFM. The computer program would then adjust the ultra-efficient variable speed blower to achieve the setpoints of the thermostat and humidistat. It would satisfy the setpoint of the humidistat first, then the thermostat setpoint.

The outdoor computer would sense the air temperature and the condenser discharge air temperature and pressure temperature and using the btu/hr formula provide the digital readout of the actual btu/hr of heat being transferred to the outside by the evaporator coil and the condenser.

Optimizing the Evaporator BTU/hr Heat Input  Important - Do First !

The condenser's ultra-efficient variable speed motor would keep the condenser pressure/temperature at a predetermined setpoint for optimal efficiency of operation in all weather temperature conditions. The compressor would have a temperature activated crankcase heater to keep any condensed liquid refrigerant boiled out of the compressor's oil.

The charts and formulas I illustrate in my other air-conditioning pages would be easily applicable to the specific operational specifications of the individual units.

Below is part of the thread from my alt.hvac News Group Post

Paul, since I'm not a HVAC guy, I'd appreciate you explaining the acronyms mentioned (in your post) ... particularly EEV, ADP and SHR.
- Marc

EEV "Electronic" Expansion Valve - a refrigerant metering device similar to a TVX in that it modulates, but controlled by an internal stepper motor subject to external control signal modified by a computer board, often derived from a thermistor on the leaving suction line. Various ramps are available - 4 - 20 ma, 0 - 5 vdc, etc.

ADP -Apparatus Dew Point - the dew point temperature of a cooling coil in a system.

SHR - Sensible Heat Ratio - the relationship of latent to sensible heat, expressed as sensible heat / total heat.
Oh - you wanted to know  'why bother' ?

As you control superheat via the EER Electronic Expansion Valve, you change the SHR Sensible Heat Ratio of the coil by lowering or raising the ADP Apparatus Dew Point.

Thus, for a humid day, more dehumidification, you open the EEV ( more control voltage ), which lowers the superheat, which lowers the ADP, which makes the system pull more latent heat as opposed to sensible.

Thus, it's a better dehumidifier than before. Especially good on cool humid days, when it's difficult to control comfort conditions without overcooling.

On a real hot dry day,you can raise the superheat(close the EEV some), and pull more sensible heat than before in relation to latent, IE, address the humidity later, after peak hours. - Paul - pjm
That is an example of a couple of computerized applications, there are many more. Your air-conditioner could be operating optimally for whatever quality of comfort you want to achieve.

The value-added marketing points are far too numerous to list here.
Page 618, Refrigeration & Air-Conditioning (ARI) Second Edition, C 1987

Sorry, I defiled the graph, 90-db outdoor, 80-db indoors with 67 wet bulb/50% RH represents the condenser splits shown above.
Air Temperature Drop Through Evaporator Coil (1987 Period)
Indoor temperature and humidity load variations graph.
Refrigeration & Air-Conditioning (ARI) Second Edition,
Page 624,
© 1987

     - udarrell    - Darrell

In the Grant county Wisconsin and adjacent areas of Beetown;Cassville;Potosi; Dickeyville;and Lancaster,Wisconsin,I would call and discuss your problems with-

Myers Heating and Cooling, LLC.,
Lancaster, WI 53813
Tel. 608-723-6543

"Getting it RIGHT, makes all the difference in the world."

If you want to discuss the AC test checks you can do to know how well your AC system is performinmg, I'm in the Beetown; Cassville; Potosi; Dickeyville; Lancaster, Wisconsin - Beetown section of the TDS telephone book directory, under Darrell Udelhoven, give me a call.

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