Introduction
The fourth working phase IEA-EBC Annex 85 Online Workshop was held on July 21st, 2022 at Beijing, using ZOOM meeting room. The meeting was opened by Associate professor Xiaoyun Xie. This workshop focuses on the performance indicators of IEC/DEC technologies discussion, also including two presentations about analysis on experimental or filed testing results of IEC/DEC systems. Seven research presentation were given by participants. General idea of the following cooperation research of Annex 85 and the performance indicators of IEC/DEC systems were discussed.

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. (2 presentations, 40 mins for each one)
  • Instant District Cooling System. (Hicham Johra, 15min+25min, 11:15~11:55)

The presentation is about the measurement and monitor of a cooling system in Denmark. The results show that most of the operation modes are indirect evaporation.

• Testing performance of IEC water chiller and its components. (Xiaoyun Xie, 10min+5mins, 11:55~12:10)

The presentation shows pressure drop of an IEC water chiller, the performance of two air coolers, and the mass transfer coefficient of different sizes of paddings. Give replies for Prof. Jean Lebrun for questions and have some deep discussions.

• Modeling on IEC water chillers processes based on field testing data. (Jean Lebrun, 15min+25min, 12:10~12:50)

The presentation introduces the modeling on IEC water chillers processes based on field testing data. From simulation results, both air and water sides have to be considered with great care and system sizing and optimal control are of crucial importance

• General idea of the following cooperation research of Annex 85. (Xiaoyun, Xie, 15min+10mins, 12:50~13:15)

The main difficulty for progress of Annex 85 is that we have not set up a unified indicators system to identify the process performance. Give general idea of the following cooperation research.

•  Indicators discussions
  • Dew point indirect evaporative cooler: KPI, Seer and Hybrid system. (María Jesús Romero-Lara, Francisco Comino and Manuel Ruiz de Adana, 25 mins, 13:15~13:40)

The presentation shows Dew point indirect evaporative cooler: KPI, SEER and Hybrid system. The UCO team defined expressions of several key performance indicators for IEC, proposed a simplified SEER calculation methodology for IEC and designed the energy behavior of a hybrid air-cooling system.

• Possible indicators of IEC/DEC processes. (Stefano De Antonellis, 20 mins, 13:40~14:00)

The presentation discusses possible indicators of IEC/DEC processes.

• Performance of indicators for IEC processes under various climate conditions. (Xiaoyun Xie, 15mins, 14:00~14:15)

Give the performance of indicators for IEC processes under various climate conditions. The indicators varies slightly when climates changes. For different process structures, the performance of indicators is different.

• Summary and adjournment (all participants, 14:55~15:00)

Main points and topics of the workshop

•  Research presentations of IEC/DEC system
  •  Introduced an instant District Cooling System in Denmark.
  •  Both air and water sides have to be considered with great care and system sizing and optimal control are of crucial importance.
•  General idea of the following cooperation research of Annex 85.
  •  Set up a unified indicator system: choose suitable indicators; feasibility analysis using the indicators system; energy consumption analysis.
  •  Discuss the basic modeling of different IEC/DEC process, form basic understanding and formulas used for heat and mass transfer processes inside.
  •  Need a unified nomenclature.
•  Indicators discussions
  • Defined expressions of several key performance indicators for IEC, proposed a simplified SEER calculation methodology for IEC and designed the energy behavior of a hybrid air-cooling system.
  • Possible indicators of IEC/DEC processes: Wet bulb/ dew point effectiveness (IEC) and saturation efficiency (DEC); Dry bulb effectiveness (IEC); Temperature depression & cooling capacity; Fraction of evaporated water & energy efficiency ratio; Pressure drop.
  • For different process structures, the performance of indicators is different.

Progress

•  Exchanged the research result between the participants.
•  Discussed the General idea of the following cooperation research of Annex 85.

Follow up

•  The topic and the arrangement of the next workshop
•  Chose suitable indicators.