IEA EBC Annex 85: 8th Workshop

October 26, 2022
Zoom meeting room
Zoom meeting room

This workshop in October 2022 is the 8th workshop of Annex 85, this workshop focuses on the modeling discussion of IEC/DEC processes, performance indicators of IEC/DEC technologies discussion, also including loss analysis IEC processes. The progress of each subtask and the time schedule of the final reports could also be discussed on this workshop.

Main Content of the workshop (21st July 2022, UTC: 11:00~15:00)

  • Welcome and introduction (all participants, 15 mins, 11:00~11:15)
  • Research presentations of IEC/DEC system. (3 presentations, 40 mins for each one)
    • Modeling, loss analysis and indicators discussion of IEC air coolers. (Jiale Fan, 25mins+15mins, 11:15~11:55)

The presentation is about the modeling, loss analysis and performance indicators discussion of IEC processes. Comparing the single-stage and two-stage processes gives that the supply air temperature may depend more on the mismatched thermal resistance. Dew point efficiency has been selected as a performance indicator.

  • Indicators of IEC water chillers. (Ce Zhao, 15mins+25mins, 11:55~12:35)

The presentation compares two ways to find the appropriate indicators for IEC water chillers to obtain the outlet water temperature. For parallel-connected IEC chillers, defining η_ev and η_c two efficiencies has a better effect rather than the single dewpoint efficiency under various climate conditions. But for the series-connected chillers, no conclusion yet because of the series structure itself.

  • Modeling and performance analysis of cooling towers. (Jean Lebrun, 15mins+25mins, 12:35~13:15)

The presentation introduces the performance analysis of cooling towers based on testing data. And discuss the pressure drop and heat transfer coefficient. Compared the measured data with the data provided by the manufacturer, it is found that the measured data is far less than the data provided by the manufacturer.

  • Progress of subtasks. (subtask leaders and participants, 15 mins for each one)
    • Subtask A. (Alireza Afshari, 15 mins, 13:15~13:30)

The presentation focus on investigation of climate date of the world, including extremely hot conditions, the building feature, the running mode of air conditioning, indoor design parameters and heat load.

  • Subtask B. (Stefano De Antonellis and Kashif Nawaz, 15 mins, 13:30~13:45)

The presentation discussed performance and cost analysis of IEC/DEC technologies, including cooling performance indication and analysis for IEC/DEC processes and contribution to phenomenological modeling

  • Subtask C. (Xiaoyun Xie and Hasan Demir, 15mins, 13:45~14:00)

The presentation discussed the main task is to obtain the suitable system design principle between IEC air coolers and IEC water chillers and to give the optimization method of process structures for both IEC air coolers and IEC water chillers.

  • subtask D. (Vincent Lemort and Chadi MAALOUF, 15mins, 14:00~14:15)

The presentation showed that for the team of Chadi has developed an EES model for a dew point heat exchanger that have been validated experimentally, and for the team of Vincent have investigated several types of heat exchangers including indirect evaporative cooling.

  • Discussions between all the participants (all participants, 14:15~14:45)
  • Summary and adjournment (all participants, 14:55~15:00)


Main points and topics of the workshop

  • Research presentations of IEC/DEC system

The thermal resistance in the heat and mass transfer process can be used as a measure to compare different processes.
For parallel-connected IEC water chillers, defining  η_ev and η_c two efficiencies are more suitable under various climate conditions.
Have some good orders of magnitudes about all transfer coefficient and corresponding pressure drops on air side.

  • Indicators discussions

Study the performance of different indicators with varying climate conditions, choose the indicators which are stable or varies slightly with climate conditions.
Suitable performance indicators can guide manufacturers to improve device.


  • Exchanged the research result between the participants.
  • Several performance indicators are proposed.
  • Discussed the time schedule of the final reports of Annex 85.

Follow up

  • Compare the modeling methods of different models.
  • Chose suitable performance indicators of IEC/DEC processes.
  • Hold some seminars for one subtask or one process, and interested members can participate.