Royal Court of Appeals

The Royal Court of Appeal for Western Sweden is in central Gothenburg. The building is 6 stories tall and hosts 110 offices, 8 courtrooms and a library in 5,070 sqm. The building is owned and operated by Platzer commercial real estate company managing 800km2 of property in western Sweden. 

The building has had problems with the cooling system for a long time; optimal comfort could not be achieved in the offices and courtrooms.

The Project

The Royal Court of Appeal for Western Sweden is in central Gothenburg. The building was originally built in 1926 as headquarters for Broströms Rederi AB, an important shipping company, and in 1994 became the Royal Court of Appeals of Wester Sweden and has been used for this purpose since. The building is 6 stories tall and hosts110 offices, 8 courtrooms and a library in 5,070 sqm. The building is owned and operated by Platzer commercial real estate company managing 800km2 of property in western Sweden.

The Hydronic Challenge

The building has had problems with the cooling system for a long time; optimal comfort could not be achieved in the offices and courtrooms. The temperature difference of the district cooling was between 2°C and 3°C resulting in poor energy performance and high energy bills. The cooling system has a capacity of 160 kW and is operated by district cooling, serving chilled beams and two Air Handling Units (AHU). The heating system has a capacity of 350 kW and is used by district heating that serves radiators and the two AHUs.

The two AHUs serving the building have two batteries each, one for heating and one for cooling. The AHU uses a rotary heat recovery unit between the exhaust and supply air and compensates the temperature with either heating or cooling to reach the target inlet temperature of the air. The air is then distributed in a variable air volume (VAV) system to the different parts of the building.

Both AHUs were previously served with standard control valves. Since there are no differential pressure controllers in the systems, the standard control valves had significant variations in available pressure (poor authority). As a result, the control of the inlet air temperature fluctuated. The dirt in the system and fouling on the heat exchangers caused the system to be unable to exchange the temperatures between the district cooling and the hydronic network, causing system inefficiencies and big pressure drops in the system.

Figure 1 Illustration of one of the Air Handling Units (AHU 1)
Figure 1: Illustration of one of the Air Handling Units (AHU 1) 
 
 

The Solution

In 2021 a renovation of the system was made to get the system working properly. The renovation aimed to improve the water quality in the system and the air handling unit's performance in controlling the room temperature.

Water Quality Improvement: 

  • Cleaning the plate heat exchanger to the district cooling 
  • Installation of filters, flush and replace existing water

Air Handling Unit Renovation: 

  • Changed the fan and battery on the unit
  • Installing TA-Smart 

After the energy renovation, the system has improved its performance with a stable indoor climate and energy efficiency. During the previous 9 months, the room temperature has never deviated more than ± 1°C and is usually within ±0.5°C. The temperature difference on the district cooling primary side is now improved and is between 8°C and 10°C instead of between 2°C and 3°C.

 

Case study 2

Figure 2: The TA-Smart DN40 on the primary side of the injection loop serving the AHU 1 battery

 

Case study 3

Figure 3: The TA-Smart DN65 on AHU 2

 

Case study 4

Figure 4: Room temperature average after the renovation

 

Marcus Andersson, the technical manager for the courthouse, wanted to try the TA-Smart to solve the problems
they had with indoor climate and energy performance.

“We knew we needed to improve the building. I have always promoted pressure-independent solutions, either Differential pressure controllers (DPCV) or pressure-independent balancing and control valves (PIBCV). TA-Smart is the next step and I wanted to test how well it performed. What I like is that you get all the data and that it’s very easy to commission. The data really helps identify what the problem is.”.

Platzer as a company, has a target to reduce the bought energy by 2% every year. “The low-hanging fruit in energy savings has already been taken. We need to think differently to reach our energy targets. The first step is to know when the energy is consumed. The second step is to control where the power should go in an optimal way. TA-Smart is doing both and is a key for us to improve further”.

“We are very happy with how TA-Smart have performed in this installation. We usually try new technology on a small scale before we use it more broadly. Because of how well this test has gone we are now installing 17 more TA-Smart in another renovation we are doing.” - Marcus Andersson, Technical Manager

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