Sensible Equipment Company, Inc.

TRICOIL® Air Conditioning Method
The Sensible SolutionTM

P.O. Box 669 Goldenrod, FL  32733  ·  tel: 407-296-8068  ·  fax: 407-296-7420  ·  email: kle@tricoil.com

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PERFORMANCE
TRICOIL® METHOD: PUMP ON/OFF COMPARISON

The TRICOIL® method adjusts the air handling unit's Sensible Heat Ratio (often called Sensible Heat Factor) to better match the cooling load of the room as indicted by the Room Sensible Heat Ratio. For example, consider the following performance of a unit with the TRICOIL® system pump OFF and with the TRICOIL® system pump ON.

  PUMP OFF PUMP ON
AIR VOLUME 10000 CFM 10000 CFM
ENTERING AIR TEMPERATURE
HUMIDITY RATIO		 80°F DB / 67°F WB
0.0113 lb water / lb dry air		 80°F DB / 67°F WB
0.0113 lb water / lb dry air
SUPPLY AIR
TEMPERATURE
DEWPOINT
HUMIDITY RATIO
55°F DB / 53.8°F WB
53°F Dewpoint Temp
0.0085 lb water / lb dry air
59.5°F DB / 53.8°F WB
49.5°F Dewpoint Temp
0.0075 lb water / lb dry air
UNIT COOLING PERFORMANCE
SENSIBLE
LATENT
TOTAL
UNIT SENSIBLE HEAT RATIO
293.0 MBH
134.2 MBH
427.2 MBH
.69 SHR
244.1 MBH
183.1 MBH
427.2 MBH
.57 SHR
ROOM COOLING EFFECT
SENSIBLE
LATENT
ROOM SENSIBLE HEAT RATIO
217.0 MBH
38.7 MBH
.85 SHR
168.2 MBH (22% decrease)
87.1 MBH (123% increase)
.66 SHR

The effect of the pump on/off cycle is a change in the air conditioning unit's sensible heat ratio. The low sensible heat ratio when the pump is on (0.57) indicates that the unit provides more dehumidification in proportion to the total cooling. Conversely, when the pump is off the system's sensible heat ratio is higher (0.69) indicating the unit provides less dehumidification in proportion to the total cooling.

Typical air conditioning applications are characterized by a cooling load having a moderate to high sensible heat ratio at full load operation and a low sensible heat ratio at partial cooling load periods. For this example the pump is turned on for the partial cooling load providing a room sensible heat factor of 0.66. When the indoor temperature rises, indicating full indoor cooling is required, the pump is turned off providing a room sensible heat factor of 0.85. Turning the pump off shifts a portion of the unit's latent room cooling capacity to sensible cooling capacity. Conversely, turning the pump on shifts a portion of the sensible cooling capacity to latent cooling capacity.

This Psychrometric chart illustrates the pump on and pump off operation of the TRICOIL® Method.

Send mail to kle@tricoil.com with questions or comments about this web site.
Copyright © 2009 Sensible Equipment Compnay, Inc.
Last modified: August 05, 2009