Sustainable cooling and heating at the Me and All Hotel
“GreenSign” hotel with Hybrid VRF system
KielThe Lindner Me and All hotels are a boutique brand of Lindner Hotels AG and combine urban design with a local twist, high quality, fabulous details, the finest technology and a living room flair. In GreenSign-certified hotels, sustainability, energy efficiency and environmental protection occupy a key role in energy supply. The air-conditioning system at the Kiel site, for example, not only uses all of its waste heat for heating in simultaneous operation, but also heats theDHW.
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Requirements:
- Energy-efficient air conditioning and heating technology
- centralised control with energy monitoring
- individual air conditioning for each room
Requirements – sustainability in heating, cooling and DHW production
RequirementsWith emphasised regionality, a strong local network and efficient sustainability management, the hotel management ensures each and every day that the CO2 footprint is as small as possible. Me and All hotels have been awarded the leading European “GreenSign” sustainability certificate. Sustainability, energy efficiency and environmental protection play a key role. For example, an intelligent hotel room management system alone significantly contributes to reducing energy consumption by around 25 %. So – how does the building energy technology set-up look like at the Me and All Hotel Kiel, in particular the air-conditioning and heating system technology?
In order to meet the “GreenSign” certificate standards, one of the key requirements for the air-conditioning technology was energy efficiency, i.e. using a method to employ the energy in the best way, for example through heat recovery. Another important point was a centralised control and integration into a building management system to carry out continuous energy monitoring – with the capability of optimising energy consumption at any time. As a third important task, the air conditioning should offer hotel guests maximum individual comfort in their rooms when selecting their preferred temperature.
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We proposed to the hotelier an air-conditioning technology that combines with comfort and safety while protecting the environment. Our approach combines the high demands of this modern hotel concept with high efficiency and comfort requirements.
Advantages of the Hybrid VRF system
BenefitsHeat recovery reduces energy consumption
The solution was the development of a complex building technology system concept focusing on comprehensive heat recovery. A key element in this approach is the air-conditioning technology used, which is intrinsically equipped with a particularly energy-efficient heat recovery system. The heat recovery of the entire building technology system includes all heat generators. For example, domestic hot water (DHW) and dedicated heating are provided by a combined heat and power plant (CHP) operated by municipal utilities on a contracting basis.
Excess heat energy or heat energy not required in the short term is stored in a 2,500-litre buffer tank and can be retrieved at any time – thanks to smart temperature stratification with corresponding sensors. In addition to static heating surfaces, the air-conditioning units are also connected to this buffer tank, significantly increasing energy efficiency and thus considerably reducing both consumption and associated costs. Only heat that is not actually required will be ultimately dissipated via a recooling system on the roof.
Comfort: individual temperature for each hotel room
A climate-friendly and highly efficient air-conditioning system has been installed to comfortably air-condition the hotel rooms and public areas at all times. The hybrid 2-pipe system combines the benefits of a direct evaporation system with those of a water-cooled system.
Thanks to the separation into a refrigerant-based and a water-based section, this system gets by with a reduced refrigerant charge, as the refrigerant only circulates between the outdoor units and the manifolds known as Hybrid BC controllers. 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.
No refrigerant in hotel rooms: Water-based outdoor units for indoor installation
Water-based PQRY series HVRF outdoor units for indoor installation – also known as water modules – are being applied to use the excess heat energy for DHW heating. For each hotel room floor, three water-cooled outdoor units are used. Two further units of the same type supply the indoor units on the ground floor. Each unit has a cooling output of 33.5 kW and a heating output of 37.5 kW. Together, the fourteen units have a cooling output of 469 kW and a heating output of 525 kW. There is a dedicated Hybrid BC Controller for each outdoor unit to which the indoor air-conditioning units are connected.
The heat transfer from refrigerant to water serving as transport medium occurs in the Hybrid BC controllers. Depending on the heating or cooling demands, the controller units forward hot or cold water to the indoor units in the guest rooms and common areas. The heat recovery function of the Hybrid VRF system ensures that heat extracted from the rooms that require cooling is not released into the environment, but is used instead via the Hybrid BC Controllers to heat the rooms that require heating. Thanks to the use of the HVRF air-conditioning system, the Me and All Hotel in Kiel, Germany, completely gets by without conventional heaters in the guest rooms.
All 164 hotel rooms are heated or cooled exclusively by the Hybrid VRF air-conditioning system. The required indoor units (1 for each guest room) are ceiling concealed ducted units located in the entrance areas of the rooms. On the ground floor, all public areas are air-conditioned using ducted units for visible installation. “Thanks to this innovative technology, we were able to implement a project in which refrigerant pipes in the hotel rooms were to be expressly dispensed with”, says Nico Lange, project manager at Koll Kälte-Klima-Lüftung GmbH & CO. KG.
Centralised control with energy monitoring: for energy efficiency and comfort
The convenient operating concept demands particular attention. In the individual rooms, guests have the option of setting their preferred temperature via the remote control’s user-friendly touchscreen. The elegant PAR-CT01MAA hotel remote control can also be conveniently configured and operated via an app. All air-conditioning units on each floor are also connected via an EB50 central remote control and linked via an IP network. Furthermore, hotel staff have two AE200 visual central control systems available in the technical room.
They enable access to all indoor air-conditioning units and make it easier to perform monitoring and check status displays from a central point. Beyond that, an additional Energy Management Licence Pack allows the transmission of data on energy consumption and provides energy-saving features. At this control level, a predefined default setting is implemented for each room as well, which will be activated automatically when a room is not occupied or a guest leaves or switches off the air-conditioning in the room. This makes the hotel operator’s work easier and saves energy and costs as well.
Mitsubishi Electric’s Remote Monitoring Interface (RMI) is used in the Me and All Hotel in Kiel, Germany, to permanently monitor the air-conditioning technology and to provide the building management system with relevant operating and energy data. The RMI is a cloud-based software solution for visualised control and supervision of air-conditioning systems via smartphone apps or web browsers. A maintenance tool provides maintenance companies with the access to the in-house network and visualises the system operating data. It also enables the operator to analyse consumption data and monitor energy costs for the individual building units.
The key points
Summary- The Me and All Hotel in Kiel not only impresses with its stylish appearance. But above all, it is its modern concept, which provides – in addition to a good work-life balance – emphasises the respectful use of global resources.
- A special contribution is made by the modern and highly efficient Mitsubishi Electric Hybrid VRF air-conditioning system, which allows simultaneous heating and cooling operation with heat recovery.
- The hybrid 2-pipe system combines the benefits of a direct evaporation system with those of a water-cooled system.
- Thanks to the separation into a refrigerant-based and a water-based section, this system gets by with a reduced refrigerant charge in the building, as the refrigerant only circulates between the outdoor units and the Hybrid BC controllers.
- It was possible to integrate the air-conditioning technology into a higher-level building management system by using water-based outdoor units.
- The excess heat energy of the air-conditioning system is stored in a buffer tank and used to preheat the DHW, significantly increasing energy efficiency and considerably reducing consumption and associated costs.
