FR

FR Company Air Conditioner Test Room Project

 

Creation of specific conditions at defined points on the psychrometric chart, with precise temperature and relative humidity control in 10 to 12 operating modes, for testing split-type air conditioning systems.

The project included two separate test rooms: one for the indoor unit and one for the outdoor unit (condensing unit), each with independent test conditions. This project was implemented for an importing and manufacturing company of air conditioning systems.

Grad Company, upon the request of a knowledge-based company whose board of directors consists of mechanical engineering professors from the University of Tehran, successfully provided the designed psychrometric test points by supplying fully intelligent air handling units and special compression chillers capable of above-zero and sub-zero operation.

FR Company is a major importer and assembler of split-type air conditioning systems located in the city of Abadan. In order to obtain product standard certifications, performance testing of the units was required. Therefore, by engaging a qualified and approved company with the necessary technical expertise, FR Company proceeded with the establishment of dedicated product test rooms.

Project Conditions:

  1. Two separate test rooms, including an indoor unit test room and an outdoor unit test room.
  2. Provision of six psychrometric points for the indoor unit and six psychrometric points for the outdoor unit in both summer and winter conditions, totaling 24 psychrometric points.
  3. Installation of air-cooled chillers in two types: above-zero and sub-zero operation, suitable for Abadan’s climatic conditions.
  4. Equipment designed for four-season operation.
  5. Indoor unit test room capacity range: 12,000 to 60,000 BTU/h.
  6. Outdoor unit test room capacity range: 12,000 to 60,000 BTU/h.
  7. Six operating modes (six psychrometric air points) for the indoor unit in summer.
  8. Six operating modes (six psychrometric air points) for the indoor unit in winter.
  9. Six operating modes (six psychrometric air points) for the outdoor unit in summer.
  10. Six operating modes (six psychrometric air points) for the outdoor unit in winter.
  11. All above conditions were required to be achieved with an accuracy of ±0.1°C and ±3% relative humidity.

Challenges:

  1. Achieving precise temperature and relative humidity conditions at specific points on the psychrometric chart required air handling units equipped with multiple heating and cooling coils. To enable stepwise movement across the psychrometric chart, the AHUs were designed and manufactured with three stages of chilled water cooling coils, two stages of electric heating coils (SSR-controlled), and variable-speed fans to adjust airflow rates.
  2. One of the most critical aspects of the project was the control algorithm and related control devices. These required highly specialized programming to ensure all AHU components operated according to the required conditions. This included chilled water coil temperature control via thermostatic valves and linear control of electric heating coils through SSRs. Based on the control algorithm, the priority and sequencing of each coil stage were continuously adjusted in real time to reach the design point with an accuracy of ±0.1°C.
  3. The design, manufacturing, and commissioning of one of the chillers was particularly critical. The chiller had to operate reliably throughout all four seasons in Abadan’s climate, with summer ambient temperatures reaching up to 50°C, while still being capable of cooling the fluid to -20°C. Considering compression ratios and the use of ethylene glycol in the water circuit, a chiller with the required actual capacity was designed, installed, and commissioned.
  4. Precise control of all thermodynamic parameters was another major challenge. Through specialized and accurate programming—covering thermodynamic parameters, coordination between chillers and AHUs, and the required operational accuracy—the system was successfully implemented. Monitoring of four systems was integrated into a single HMI screen to facilitate ease of operation and supervision.

 

Project Results:

 

  1. Commissioning of two fully intelligent air handling units, each operating independently and dedicated to its respective test room with different conditions.
  2. Commissioning of an above-zero air-cooled compression chiller for the indoor unit test room AHU.
  3. Commissioning of a sub-zero air-cooled compression chiller for the outdoor unit test room AHU.
  4. Integrated monitoring of all equipment as a unified package for control, adjustment, and observation of all required parameters.