HVRF system with river water as energy source
Reference for efficient cooling and heating at the BASF Creation Center
Ludwigshafen am RheinWith its Creation Center, the globally renowned chemicals company BASF has established a hub where its most creative thinkers can work together with customers from the field of performance materials – using their knowledge of materials to develop tailored plastic solutions. The building is located in a spectacular setting, perched atop a former air-raid shelter and featuring a stunning facade. It also houses a remarkable Hybrid VRF air conditioning solution in which water-based outdoor units for indoor installation use river water as an energy source.
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Requirements:
- Installation on roof or outdoors not permitted due to historical preservation regulations
- Innovative solution true to the BASF sustainability strategy
- Energy-efficient and environmentally friendly solution
- In line with the latest technical developments
- Simultaneous cooling and heating
- Low refrigerant use
- Smart control and high comfort
Initial conditions
Initial conditionsFor the construction of the new BASF Creation Center, a former air-raid shelter at the company’s Ludwigshafen site was fitted with a cube featuring 24-metre sides. This structure provides around 1,000 m2 of additional floor space across two storeys. The Creation Center is a place where BASF customers can meet designers and specialists from the field of performance materials, working together to simulate particular requirements. Alongside new offices and seminar rooms, the cube perched atop the former shelter is characterised above all by its large central space. This is modelled on a lecture theatre and combined with a workshop. Workstations for BASF employees are complemented by additional workstations that are ready for a flexible range of uses. Finally, the spectacular mounted facade plays with the effects of light and shadow to provide an eye-catching attraction.
Challenges
Challenges
Technical building services also posed a series of demanding requirements, namely how to operate the building in an energy-efficient manner and guarantee flexible use. The ventilation system, chiller and heat supply system were planned on behalf of BASF Wohnen + Bauen (BWB) by Markus Schwalb, Managing Director of the Ludwigshafen-based engineering agency for energy and system consulting Enacon GmbH.
One of the challenges was that the shelter is a protected historical building, meaning that the relevant preservation authorities were also involved in the approval process. Since building law prevented any installation on the roof or outdoors, it was not possible to perform outdoor installation of classic air-cooled VRF outdoor units. “Other potential approaches, such as a classic district heating supply in combination with a direct evaporation system for cooling, were considered during the preliminary planning phase,” explains Schwalb. However, this flagship project demanded the implementation of an innovative solution that would embody the BASF sustainability strategy in being as energy-efficient and environmentally friendly as possible while also representing the current state of the art.
Which solution was chosen for the BASF Creation Center?
HVRF systemHybrid VRF system with river water as sustainable primary energy source
This challenge was met by connecting to an existing BASF river water system and using this as the primary energy supply for the heat pumps. The operating principle of this system concept is simple and effective: the river water is pumped out of a well and the heat is output from the primary circuit to the secondary circuit via a plate heat exchanger. This secondary circuit transfers the energy to the refrigerant in the air conditioning units.
All of this takes place in a technology room in the basement of the stair tower and the river water is drawn directly from the BASF river water network system. The Hybrid VRF R2 system from the Mitsubishi Electric City Multi series is the solution used here, with the river water handling the sustainable supply of energy to the water-based heat pumps. The Hybrid VRF R2 system is the first 2-pipe system to provide simultaneous cooling and heating with heat recovery, combining the benefits of a direct evaporation system with those of a water-based system. With the water-based outdoor units for indoor installation – also known as water modules – the manufacturer sets a high standard and considerably expands the potential application areas of the Hybrid VRF system, because the water modules are compatible with all standard indoor units from the City Multi series. Three water-cooled outdoor units that combine to provide 110 kW of heating capacity or 100 kW of cooling capacity are deployed in this particular case.
A further boost for the sustainability concept
SustainabilityOne positive aspect of Hybrid VRF technology is the separation of the system into a refrigeration-based part and a water-based part, which enables the system to operate with a reduced refrigerant charge quantity. As the operation of the system requires only minimal use of refrigerant, the incurred maintenance costs are significantly lower because chillers on this scale must be inspected at regular intervals. This also promotes an element of the sustainability concept for this building: the refrigerant only circulates between the outdoor units and the Hybrid BC Controllers (distributor units) that are located in a storage room on the respective floor.
The Hybrid BC Controllers form a frost-free cooling and control entity together with the outdoor units, meeting the heat or cooling demand by directing hot or cold water to the various air conditioning circuits of the indoor units. This enables individual heating or cooling of each area. The innovative Hybrid VRF system also stands out on account of its high energy efficiency without loss of comfort. The heat recovery function means that heat extracted from the rooms requiring cooling is not output to the river water; with the help of the Hybrid BC Controllers, it is instead used for heating the rooms that require heat. Only excess thermal energy is output to the river water. In this way, the BASF Creation Center does not require a conventional heating system and therefore does not consume any fossil fuels. The interior of the controller houses all components except for an expansion vessel. Plate heat exchangers for the transition from refrigerant to water, pumps and valves are already integrated into the housing and ready to operate.
Optional heating and cooling for the entire BASF Creation Center is handled solely by the Hybrid VRF air conditioning system. The 35 indoor units required for this purpose feature an exposed installation as ceiling cassettes or ceiling concealed units or are integrated into the ceiling in the case of suspended constructions. One impressive feature of the Hybrid VRF system is that, with only two pipes per indoor unit, it permits a customised temperature (free selection of heating and cooling modes) for each individual user – regardless of the time of year, time of day or outside temperature. In addition, the extra water circuit enables the system to provide stable and mild blow-out temperatures that are considered extremely pleasant.
3D i-see sensor adjusts capacity to meet demand
ControlIntelligent and convenient operating concept
The convenient operating concept demands particular attention. The indoor units in the individual rooms and climate zones have been integrated into a superordinate building management system, with all employees able to conveniently control these from their work PCs. Access to the type AE200 visual central control system is also available on every floor. The control system makes it easier to perform monitoring and check status displays from a central point. A maintenance tool provides access to the in-house network and visualises the system operating data. This has made it possible to implement a load shedding circuit, for example, which prevents unnecessary power consumption. A predefined standard setting is also stored for each room at this control level.
In addition, all indoor units are equipped with 3D i-see sensor technology for intelligent air conditioning and high levels of comfort. The 3D sensors inspect the room, detect whether any persons are present and adjust the temperature accordingly. Besides saving energy, this ensures a high standard of comfort since air is not blown directly at the persons in the room. As the outdoor and indoor units are connected to the 3D i-see sensor technology, the units enter an expanded energy-saving mode that makes it possible to reduce the compressor capacity. This enables automatic energy-saving operation in locations where the number of persons present changes frequently and the heat loads that need to be dissipated are therefore lower. If the number of persons present in the room should increase, the compressor raises its capacity accordingly.
The key points
Summary- With its Creation Center in Ludwigshafen, BASF has implemented a new integrated concept for its Performance Materials division.
- An extension was added to a former air-raid shelter for this purpose. The existing building was extended by two additional storeys offering around 1,000 m2 of floor space.
- Just as innovative is the newly installed air conditioning system, which uses river water as an energy source and supports highly sustainable operation via its heat recovery function.
- Used for simultaneous cooling and heating, the Hybrid VRF R2 system from the Mitsubishi Electric City Multi series combines the benefits of a direct evaporation system with those of a water-cooled system. It therefore requires a considerably lower refrigerant charge quantity.
- This system deploys three water-based outdoor units for indoor installation, which use the controller to transfer the energy to the indoor units via the medium of water.
- Each indoor unit can be operated independently in heating or cooling mode. Thanks to the heat recovery function, heat extracted from the rooms requiring cooling is used for heating the rooms with a heat demand.
