Norwegian Hospital Installs CO₂ Air Conditioning

Danish OEM Advansor overcame the challenge posed by a very small machine room to install a CO₂ (R744) air conditioning system at the Haukeland University Hospital in Bergen, Norway.

The “extremely limited” space in the machine room at the hospital resulted in a “compact design that meets the space requirements and utilizes every square centimeter,” Advansor said in an article on its website.

“We appreciate that Advansor [is] solution-oriented and provide[s] expertise and experience from such facilities,” said Pål Haukeland, Project Manager with Kokstad, Norway-based Therma Bergen, the contractor installing the system. “The need for high kW cold performance, combined with the limited installation space, [and] the project was just on the limit of what is possible.”

Despite the compact space requirement, the rack chosen by the hospital is an Advansor SteelXL, which the company calls the “Tyrannosaurus Rex” of all CO₂ designs. The patented SteelXL is Advansor’s largest chiller solution to date, and it is fully customizable. It provides more than 1MW (284.3TR) of cooling on a single frame and has the coil in the receiver.

The hospital’s particular system was  a SteelXL 8+2x0 parallel solution, which has a 2.6MW (739.3TR) capacity. It includes a chiller module, heat recovery and a gas cooler. Despite its large capacity, it fits a 6.5x5m area (21.3x16.4ft). The system delivers AC water at a temperature of 7°C (45°F) and returns it at 14°C (57°F). The CO₂ leaves the gas cooler at 30°C (86°F).

Haukeland University Hospital is one of the largest in Norway, with the general area of the hospital being 200,000m² (2,200,000ft²), according to Wikipedia. In 2005 it had the largest number of patients of any hospital in Norway, according to a SINTEF report.

Low charge

Advansor said the SteelXL was perfect for the needs of Haukeland due to its low refrigerant charge and its flexible modular design. The low refrigerant charge results in a smaller receiver and reduces the system footprint, an important factor for this specific location in the center of a hospital.

SteelXL racks can be equipped with one to nine low-temperature compressors, and five to10 medium-temperature compressors. For medium-temperature applications only, they can have up to 15 compressors, resulting in capacities up to 1,400kW (398TR) per rack. 

Standard equipment for the SteelXL includes a low-temperature suction accumulator, a patented internal heat exchanger located in the receiver, liquid injection, a filter drier, a CO₂ low-level switch and a frequency inverter. Controllers available include Danfoss, Wurm, Carel, Eckelmann and RDM.

Potential add-ons include advanced heat recovery, permanent magnet motors, ejector technology, liquid sub-cooler and hot gas defrost.

“The good cooperation between Advansor and Therma Bergen AS resulted in a solution beneficial to both customer and end user,” noted Haukeland. “Advansor's flexibility about construction and design made this project possible and we've only got good to say about the cooperation.”