IEA EBC Annex 85: 9th Workshop

December 21, 2022
Zoom meeting room
Zoom meeting room

This work in December 2022 is the 9th workshop of Annex 85, this workshop focuses on the modeling discussion of IEC/DEC processes, experimental or field-testing performance of IEC/DEC processes.


Main Content of the workshop (20th December 2022, UTC: 11:00~15:00)

  • Welcome and introduction (all participants, 15 mins, 11:00~11:05)
  • Experimental or field-testing performance of IEC/DEC processes. (3 presentations, 40 mins for each one)
    • Experimental results of a dew-point indirect evaporative cooling system under different climatic conditions. (Francisco Comino, 15mins+25mins, 11:05~11:45)

This presentation gives the description and testing data of several experimental DIEC system. Several experimental tests were carried out to obtain empirical models of the DIEC-1 system. Different outdoor conditions were established to study the behavior of four DIEC systems under different climatic conditions.  In the testing data, the highest EER values, around 26 for DIEC-1, were reached for the highest outdoor air temperatures, lowest outdoor air humidity and lowest air flow. The same trend was shown in the manufacturer data of behavior of another 3 DIEC systems.

  • Field-testing results and performance analysis of a real IEC water chiller system. (Yijie Liu, 15mins+25mins, 11:45~12:25)

An application of serial indirect evaporative water chiller system was introduced.  The field-testing data was from a hospital which developed in 2012, Xinjiang Province, China. The produced cold water temperature of the system was 16-19?, which between the inlet dew point temperature and the wet bulb temperature. The cooling efficiency varied between about 0.4-0.7 with the changing inlet condition. The COP of the indirect evaporative chiller reached 10-12, and the COP of the system reached 4.5-6. The room temperature is 23-26?, and the relative humidity is 60-70%.

  • Field-testing performance of an IEC air cooler process. (POURBAIX Adrien 15mins+25mins, 12:25~13:05)

The presentation shows the performance of an IEC air cooler in a used building. Quiet hot summer day in Belgium with low dew point (more than 30? of dry -bulb in the afternoon with a dew point less than 10?). An office building with good insulation and sun protection (sensible cooling load of 6 [kW]). An increasing of the friction loss in link with the increasing of the airflow (more important for ODA-SUP). A significant power consumption for the adiabatic pumps compares with the fans. A good cooling capacity (more than 25 [kW]) and a good cooling COP (more than 7) in the afternoon.

  • Modeling discussion of IEC/DEC processes. (3 presentations, 20 mins for each one, 13:05~14:35)
    • Discussion about cooling towers. (Jean Lebrun, 15mins+25mins, 12:50~13:25)

Some performance of cooling tower was given. The information is from the tower manufacturer. The presentation gives the data about the air/water mass flow rate ratio, the pressure drop, global heat transfer coefficient, etc.

  • Cost discussion of IEC air coolers. (Paolo Liberati, Raul Simonetti, 15mins+15mins, 13:25~13:55)

The presentation talks about the cost of IEC technology. A comparison between a system w/ and w/o a IEC technology which use three climatic profiles and two different sizes. The simulation target is to minimize the AHU’s running cost (electricity + gas + water) by the proper combination of its devices’ outputs and include some Additional cost to implement the IEC solution.

  • Modeling discussion of a dew-point indirect evaporative cooling system. (María Jesús Romero-Lara, 15mins+25mins, 13:55~14:35)

Development of a simplified method for calculating the Seasonal Energy Efficiency Ratio (SEER) of dew-point indirect evaporative cooling systems (DIEC). The results indicated that the simplified SEER calculation method for DIEC systems in the Mediterranean climate region could be an effective method for calculating SEER without the need to use annual energy simulations or measurements.

  • Summary of 2022 and adjournment (all participants, 14:35~15:00)

Main points and topics of the workshop

  • The main progress of Annex 85 in 2022

New participants and groups joined in Annex 85
The goal and focus of Annex 85 is more and more clear, we are changing from summary of progresses of each group to joint research of different groups step by step.
Progress on real projects analysis, indicators definition and analysis on different IEC/DEC processes, modeling on IEC water chiller process, cooling tower process and IEC air cooler processes, simulation analysis, and so on.

  •  Work plan in 2023

Determine suitable and unified indicators, separately for IEC air coolers, IEC water chillers, and so on.
Research on world climate conditions, including temperature and humidity, under the given number of unguaranteed hours, to see which regions are suitable to using IEC/DEC technologies.
Indicators analysis of various kinds of IEC/DEC processes, to compare different process structures, including internal processes analysis inside devices.


  • Exchanged the research result between the participants.
  • Modeling discussion of IEC/DEC processes.
  • Discussed the schedule of the final reports of Annex 85.

Follow up

  • Physical meeting.
  • Chose a standard project and suitable performance indicators of IEC/DEC processes.
  • Hold some seminars for one subtask or one process, and interested members can participate.