Performance Testing of a Family of Type I Combination Appliances.
Performance Testing of a Family of Type I Combination
Appliances.
(1589 K)
Liu, S. T.; Kelly, G. E.; Terlizzi, C. P.
NISTIR 5626; 30 p. April 1995.
Sponsor:
Department of Energy, Washington, DC
Available from:
National Technical Information Service
Order number: PB95-220521
Keywords:
Annual Fuel Utilization Efficiency; ANSI/ASHRAE Standard
103; ASHRAE Standard 124; boiler; building technology;
combination appliance; combined annual efficiency; DOE
test procedure; domestic water storage tank; energy
factor; heating seasonal efficiency; integrated
appliance; linear interpolation; rating; space heating;
steady state efficiency; water heating
Abstract:
ANSI/ASHRAE Standard 124-1991 specifies the laboratory
test and the calculation procedures for estimating
seasonal and annual performance of combination
appliances which are designed to provide both space
heating and water heating. A boiler that includes a
tankless coil for water heating or in combination with
an indirectly heated storage tank is classified by
ASHRAE Standard 124 as Type I combination appliances.
It is common for single size tankless coil or storage
tank to be used in combination with a series of boilers
(called a family series) of different sizes. In an
effort to minimize the test burdens on manufacturers, a
family series of gas-fired hot water boilers were tested
to determine if a subset of a family series of Type I
combination appliances could be tested and used to
predict the performance of the rest of the appliances in
the family series. Tests were conducted on a family
series of three different size boilers (rated input of
22, 33, and 44 kW) with an identical indirectly heated
storage tank to determine their Combined Annual
Efficiency (CAE) as specified in ASHRAE Standard 124.
To this end, tests for the Energy Factor (EF) for water
heating and the Annual Fuel Utilization Efficiency
(AFUE) for space heating were conducted. For the
domestic water heating test, daily hot water draw volume
of 243.4 L (64.3 gal) was used. The results showed that
for the three boilers, the AFUE for space heating
differed by approximately 2.5 percentage points, with
the smaller size boiler having a higher AFUE. On the
other hand, the EF for water heating depended more
strongly (differed by near 5 percentage points from the
smallest (22 kW) to the largest (44 kW) capacity boilers
tested on the size of the boilers for the same daily hot
water drawn. However, the EF was an approximate linear
function of the boiler size. The results also showed
that the CAE varied by slightly over 1.6 percentage
points among the three boilers. Thus a simple linear
interpolation appears adequate for determining the
Combined Annual Efficiency (CAE) within a family series.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899