Heat wheels are used in ventilation systems to provide indoor thermal comfort by recovering considerable amount of sensible energy from exhaust airstream. The transient single step test is a new testing method developed to determine the sensible effectiveness of heat wheels. In practice, heat loss/gain may create large uncertainty in the sensible effectiveness obtained through the transient testing. In this study, the transient analytical model in the literature is extended to account for heat loss/gain effects in the transient testing. The results state that in particular operating conditions, the sensible effectiveness can be affected by more than 10% due to heat loss/gain. A new testing facility is developed to investigate the effects of heat loss/gain on the sensible effectiveness through transient testing of a small-scale heat exchanger. After decoupling heat loss/gain effects from transient test data, less than 2% difference was observed in the sensible effectiveness while supply and exhaust flow rate was small (Re < 209) and the temperature difference between them was ΔTst < 7.0 °C. However, the sensible effectiveness decreased more than 9% while ΔTst > 37.5 °C or Re > 600. An empirical correlation was proposed based on the transient test data that correlates the sensible effectiveness with the heat capacity rate ratio. Comparing the results of proposed correlation with literature, less than 2% difference was observed at the heat capacity rate ratio of greater than 0.5 after the heat loss/gain effects were decoupled from transient test data.

References

References
1.
Pérez-Lombard
,
L.
,
Ortiz
,
J.
, and
Pout
,
C.
,
2008
, “
A Review on Buildings Energy Consumption Information
,”
Energy Build.
,
40
(
3
), pp.
394
398
.
2.
Kays
,
A. L.
, and
London
,
W. M.
,
1984
,
Compact Heat Exchanger
,
McGraw-Hill
,
New York
.
3.
ANSI/AHRI
,
2011
,
ARI Standard 1060-2011, Performance Rating of Air-to-Air Heat Exchangers for Energy Recovery Ventilation Equipment
,
Air-Condition and Refrigeration Institute
,
Arlington, TX
.
4.
ANSI/ASHRAE
,
2013
,
Standard 84, Method of Testing Air-to-Air Heat/Energy Exchangers
,
ASHRAE
,
Atlanta, GA
, Vol.
8400
.
5.
Ciepliski
,
D. L.
,
1997
,
Testing an Air-to-Air Energy Recovery Device Using Performance Test Standards
,
University of Saskatchewan
,
Saskatoon, SK, Canada
.
6.
Simonson
,
C. J.
,
1998
,
Heat and Moisture Transfer in Energy Wheels
,
University of Saskatchewan
,
Saskatoon, SK, Canada
.
7.
Abe
,
O. O.
,
Simonson
,
C. J.
,
Besant
,
R. W.
, and
Shang
,
W.
,
2006
, “
Effectiveness of Energy Wheels From Transient Measurements. Part I: Prediction of Effectiveness and Uncertainty
,”
Int. J. Heat Mass Transfer
,
49
(
1–2
), pp.
52
62
.
8.
Abe
,
O. O.
,
Simonson
,
C. J.
,
Besant
,
R. W.
, and
Shang
,
W.
,
2006
, “
Effectiveness of Energy Wheels From Transient Measurements: Part II—Results and Verification
,”
Int. J. Heat Mass Transfer
,
49
(
1–2
), pp.
63
77
.
9.
Shang
,
W.
, and
Besant
,
R. W.
,
2009
, “
Effectiveness of Desiccant Coated Regenerative Wheels From Transient Response Characteristics and Flow Channel Properties—Part I: Development of Effectiveness Equations
,”
HVAC&R Res.
,
15
(
2
), pp.
329
346
.
10.
Shang
,
W.
, and
Besant
,
R.
,
2009
, “
Effectiveness of Desiccant Coated Regenerative Wheels From Transient Response Characteristics and Flow Channel Properties—Part II: Predicting and Comparing the Latent Effectiveness of Dehumidifier and Energy Wheels Using Transient Data and Properties
,”
HVAC&R Res.
,
15
(
2
), pp.
346
365
.
11.
Abe
,
O. O.
,
Simonson
,
C. J.
, and
Besant
,
R. W.
,
2006
, “
Relationship Between Energy Wheel Speed and Effectiveness and Its Transient Response, Part I: Mathematical Development of the Characteristic Time Constants and Their Relationship With Effectiveness
,”
ASHRAE Trans.
,
112
(
2
), pp.
89
102
.
12.
Abe
,
O. O.
,
Simonson
,
C. J.
, and
Besant
,
R. W.
,
2006
, “
Relationship Between Energy Wheel Speed and Effectiveness and Its Transient Response, Part II: Comparison Between Mathematical Model Predictions and Experimental Measurements and Uncertainty Analysis
,”
ASHRAE Trans.
,
112
(
2
), pp.
103
115
.
13.
Fathieh
,
F.
,
Besant
,
R. W.
,
Evitts
,
R. W.
, and
Simonson
,
C. J.
,
2015
, “
Determination of Air-to-Air Heat Wheel Sensible Effectiveness Using Temperature Step Change Data
,”
Int. J. Heat Mass Transfer
,
87
, pp.
312
326
.
14.
Bolster
,
J.
,
2012
, “
Improved Desiccant Coating for Heat and Water Vapour Transfer on the Matrix Surfaces of Air-to-Air Regenerative Wheels
,”
M.Sc. thesis
,
University of Saskatchewan Saskatoon, SK
,
Canada
.
15.
Shah
,
R. K.
, and
Sekuli
,
D. P.
,
2003
,
Fundamentals of Heat Exchanger Design
,
Wiley
,
New York
.
16.
Wu
,
Z.
,
Melnik
,
R. V. N.
, and
Borup
,
F.
,
2006
, “
Model-Based Analysis and Simulation of Regenerative Heat Wheel
,”
Energy Build.
,
38
(
5
), pp.
502
514
.
17.
Shang
,
W.
, and
Besant
,
R. W.
,
2008
, “
Theoretical and Experimental Methods for the Sensible Effectiveness of Air-to-Air Energy Recovery Wheels
,”
HVAC&R Res.
,
14
(
3
), pp.
373
396
.
18.
Shang
,
W.
, and
Besant
,
R.
,
2009
, “
Performance and Design of Dehumidifier Wheels
,”
HVAC&R Res.
,
15
(
3
), pp.
437
460
.
19.
Yilmaz
,
T.
, and
Cihan
,
E.
,
1993
, “
General Equation for Heat Transfer for Laminar Flow in Ducts of Arbitrary Cross-Sections
,”
Int. J. Heat Mass Transfer
,
36
(
13
), pp.
3265
3270
.
20.
Buyukalaca
,
O.
, and
Yilmaz
,
T.
,
2002
, “
Influence of Rotational Speed on Effectiveness of Rotary -Type Heat Exchanger
,”
Heat Mass Transfer
,
38
, pp.
441
447
.
21.
Shah
,
R. K.
, and
London
,
A. L.
,
1978
,
Advances in Heat Transfer, Laminar Flow Forced Convection in Ducts
,
Academic
,
New York
.
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