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Scope of the programme

This certification programme applies to all ranges of Air to air plate and tube heat exchangers which are included in the certified public selection software of the Applicant/Participant. The certify-all principle applies not only to Europe but to all markets.

The Applicant/Participant shall certify all models in the ranges, including:
       •   cross flow, counter-flow and parallel flow units
       •   all sizes
       •   all materials
       •   all airflow rates
       •   all edge lengths
       •   plate heat exchangers with humidity transfer
Heat exchangers with accessories such as bypass and dampers shall not be included.

The programme does not cover other types of Air to air heat exchangers like Rotary heat exchangers or Heat pipes. Combination of units (twin exchangers) shall not be included.
Definitions

Air to Air Plate or Tube Heat Exchanger
Heat Exchanger designed to transfer thermal energy (sensible or total) from one air stream to another without moving parts. Heat transfer surfaces are in form of plates or tubes. This exchanger may have parallel flow, cross flow or counter flow construction or a combination of these.

Product Range
A family of products of different size built according to the same design and using the same selection procedure.

Temperature efficiency (temperature ratio) dry
Ratio of dry temperature differences (without condensation):


with:
      •  11 = Warm air inlet
      •  12 = Warm air outlet
      •  21 = Cold air inlet
      •  22 = Cold air outlet

Temperature efficiency (temperature ratio) wet
Ratio of wet temperature differences (with condensation):


Humidity (latent) efficiency
Ratio of absolute humidity differences:


Pressure Drop
Loss in total pressure between the inlet and the outlet of a unit.

Internal Air Leakage
Air leakage between two air streams.

Nominal pressure drop and nominal air flow
The nominal pressure drop of each unit must be defined by the manufacturer. Possible values are 50, 100 or 200 Pa. The nominal airflow is the airflow which causes the nominal pressure drop.

Testing requirements

Test standard

Tests are conducted in accordance with:
EN 308 "Heat exchangers - Test procedures for establishing performance of air to air and flue gases heat recovery devices".
Particular specifications shall be applied during the test according to ECC Rating Standard 8/C/001.

Test specifications

The units shall be tested under the EN308 conditions.
The following particular specifications shall be applied during the test in the independent laboratory selected by ECC.
      •   Maximum pressure drop (Rupture pressure drop) shall be measured at a pressure difference equal to five times the nominal pressure drop:
      •   Pressure drop shall be measured for at least three air-flow rates corresponding to the pressure drop of 50, 100 and 150% of the nominal pressure drop, each +/- 10%, at least +/-5 Pa.
      •   Temperature efficiencies (dry or wet) and humidity efficiency shall be measured for three air-flow rates corresponding to 50, 100 and 150% of the nominal pressure drop, each +/- 10%, at least +/-5 Pa.

These last two bullet points result in the following table.

Table 1: Possibilities of air-flow conditions and associated acceptable deviations

Possible nominal pressure drop [Pa]

50

100

200

Corresponding nominal air flow [m3/h]

NAF50

NAF100 or qmn

NAF200

500% Pnom

Pressure difference [Pa]

250

500

1000

50% Pnom

50% of nominal pressure drop [Pa]

25

50

100

Acceptable deviation [Pa]

+/- 5

+/- 5

+/- 10

100% Pnom

100% of nominal pressure drop [Pa]

50

100

200

Acceptable deviation [Pa]

+/- 5

+/- 10

+/- 20

150% Pnom

150% of nominal pressure drop [Pa]

75

150

300

Acceptable deviation [Pa]

+/- 8

+/- 15

+/- 30

       •   Winter test for efficiency with condensation shall be performed under the following conditions:
—   The nominal pressure drop (without condensation, +/- 10%, at least +/-5 Pa) for plate heat exchangers with and without humidity transfer;
—   50 and 150% of nominal air flow for plate heat exchangers with humidity transfer (see table above);
—   The mass flow ratio of 1.0;
—   The warm air temperature of about 25°C with a humidity ratio between 45% and 75%. The inlet temperature of cold air at 0°C to -5°C (humidity is not defined).

        •   Summer test for efficiency with condensation shall be performed under the following conditions for plate heat exchangers with humidity transfer:
—  The nominal pressure drop, 50 and 150% 
—  The mass flow ratio of 1.0
—  The warm air temperature of about 35°C with randomly one of the following humidity conditions: 50% relative humidity or 14-22 g/kg. The inlet temperature of cold air at 25°C and 50% humidity.

       •   All efficiencies (in percent) shall be measured at a mass flow ratio of 1.0 with 1 decimal place and rounded normally.

These last three bullet points result in the following table.

Table 2: Testing point conditions for plate heat exchangers with and without humidity transfer

Product type

Any type

(regular point)

Without humidity transfer

With humidity transfer

Conditions

Winter dry

Winter

Winter

Summer

Summer

Mass flow ratio [-]

1.0

1.0

1.0

1.0

1.0

Warm air - temperature [°C]

~25 °C

~25°C

~25°C

~35°C

~35°C

Warm air - humidity

wet bulb
< 14 °C

45%-75%

45%-75%

50%

14-22 g/kg

Cold air inlet - temperature [°C]

5 °C

0 to -5°C

0 to -5°C

25°C

25°C

Cold air inlet - humidity

undefined

undefined

undefined

50%

50%

500% Pnom

Rupture pressure drop

Y

Y

Y

N

N

50% Pnom

Temperature efficiency dry [%]

Y

Y

Y

N

N

Temperature efficiency wet [%]

N

N

N

Y

N

Humidity efficiency

N

N

Y

Y

N

Pressure drop [Pa]

Y

Y

Y

Y

N

100% Pnom

Temperature efficiency dry [%]

Y

Y

Y

N

N

Temperature efficiency wet [%]

Y

Y

N

Y

Y

Humidity efficiency

N

N

Y

Y

Y

Pressure drop [Pa]

Y

Y

Y

Y

Y

150% Pnom

Temperature efficiency dry [%]

Y

Y

Y

N

N

Temperature efficiency wet [%]

N

N

N

Y

N

Humidity efficiency

N

N

Y

Y

N

Pressure drop [Pa]

Y

Y

Y

Y

N

  • For measuring the efficiency of the cross-flow exchangers, these shall be installed into the test rig diagonally, i.e. standing on edge, as it is common in practice. This shall no longer require any instructions of the manufacturer according to EN308, section 5.1.
  • The pressure drop (in Pa, no decimal place, normally rounded) shall be measured in the test rig in diagonal installation, i.e. standing on edge, as it is common in practice. This shall no longer require any instructions of the manufacturer according to EN 308, section 5.1. The pressure difference should be kept zero between both outgoing flows.

If any of individual points of measurement shows a deviation larger than the acceptable tolerance, the failure shall be declared and the failure procedure applied. Participants shall be free to adapt their selection documentation as they like; however the penalty test should confirm the test data.

Certified characteristics

The following performance items shall be certified.
  • Under standard conditions (20°C, 50% rel. humidity and 1.013 105 Pa - or 1.20 kg/m³ density):
—  Airflow
—  Pressure drop
  • Under winter conditions (warm air temperature: 25°C, 60% rel. humidity; inlet temperature of cold air: -3°C, 90% humidity):
—  Temperature efficiency dry [%]
—  Temperature efficiency wet [%]
—  Humidity efficiency for plate heat exchangers with humidity transfer [%]
  • Under summer conditions for plate heat exchangers with humidity transfer (warm air temperature: 35°C, 50% rel. humidity; inlet temperature of cold air: 25°C, 50% rel. humidity):
—  Temperature efficiency dry [%]
—  Temperature efficiency wet [%]
—  Humidity efficiency [%]
General Reference documents


Certification Manual 13th (November 2016)
Reference documents



OM-8-2017



RS 8/C/001-2017