USE OM - JANUARY 2017
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Section 5. Certification Requirements
5.1
Sensible Heat Capacity Evaluation of Code Tester.
5.1.1
Purpose of the Test
. The purpose of the sensible heat capacity calibration of the code tester test is to
compare the psychrometric measured sensible heat capacity to the total electrical energy input of the unit under
test. This provides a Laboratory Facility with the ability to validate that its psychrometric measurement apparatus
can measure the sensible heat capacity, prior to calibration, within 4% of the actual electrical energy input to the
unit under test. After calibration, these tests will allow for only nozzle selections for a given code tester that measure
air flow rate within 2% after correction.
5.1.2
Selection of Equipment.
5.1.2.1
Equipment Classification.
The UUT for sensible heat capacity evaluation shall be a
production split system air-handler with capability of having electric resistance heat installed internal
to the UUT.
5.1.2.2
Equipment Size and Configuration
. The production equipment design shall be fitted
with an electric heat module of at least 2 kW per maximum ton. The heater shall be made of at least
two (2) separate elements, oriented side by side, and shall be located at the outlet of the air-handler.
The UUT wiring must be modified so that electrical energy supplied to the heater may be varied
separately from electrical energy supplied to the rest of the UUT. Typically the psychrometric Outdoor
Room power supply and measurement equipment will need to be used due to relatively high power
requirements. Individual banks shall have the capability of being switched independently.
5.1.3
Test Setup.
5.1.3.1
The UUT shall be set up in the Indoor Room in accordance with ASHRAE Standard
37 Section 6.4 through Section 6.6.
5.1.3.2
All indoor electrical energy shall be measured with instrumentation which is in
accordance with Section 5.4 of ASHRAE Standard 37.
5.1.3.3
If an indoor volatile refrigerant coil is present in the UUT it shall be void of refrigerant
charge in order to eliminate any thermal siphoning.
5.1.3.4
At the outlet sampler, nine (9) individual thermocouples shall be placed in accordance
with ASHRAE Standard 116-2010 Section 7.4.3.4.1 in order to assess the ability of the Code Tester to
properly mix UUT outlet air. These thermocouples shall be out of the line of sight of the electric heat
in order to avoid radiation effects. All thermocouples shall be compliant with ASHRAE Standard 41.1
Section 10.
5.1.4
Test Procedure.
5.1.4.1
Indoor air inlet conditions shall be maintained at 70.0 ± 0.5ºF dry-bulb temperature
and 65.0 ± 0.3ºF wet-bulb temperature.
5.1.4.1.1
The Test Operating Tolerance for dry-bulb temperature shall not exceed
0.5ºF and for wet-bulb temperature shall not exceed 0.3ºF during the test.
5.1.4.2
The Laboratory Facility shall select appropriate (commonly used) nozzle combinations
to cover the air flow rate range for any foreseen Laboratory Certification Test (this range is typically
400 scfm to 2450 scfm for Unitary Small Equipment products). The selected nozzle combinations shall
be referred to as the potential combinations, a subset of all nozzle combinations. Any such nozzle
combination shall be in accordance with ASHRAE Standard 37, Section 6.3.1.
