Environment & energy


A. Optimisation of the energy consumption and building technology

1. Replacement of established ventilation system

After an intensive study of the topic of ventilation systems, we decided to go for two big changes: The replacement of the ventilation system in our dining area and the kitchen.

Compared to the old ventilation system, the new one in our FIVE Diner is highly energy-efficient due to two reasons: First, the system requires less electricity because of frequency-controlled direct current motors. Second, the exhaust air is turned into energy that is used for (pre-)heating the supply air. Therefore, additional heating with more energy resources is only rarely necessary in winter (in fact, it is only necessary when the supply air is cold and the outside temperature is very low as well – for instance in winter, when we open our restaurant in the early morning). Because our lighting in the dining area gives off quite a lot of heat unfortunately, at least we can partly re-use this heat.

The new ventilation system in the kitchen is a pilot plant in Nuremberg. Usually, kitchen facilities release high amounts of exhaust air over their housetop. That means thermal energy leaving the inside is simply wasted and the inside needs to be heated up externally by an air supply system once more. To avoid this wasting of already pre-heated air, we picked a system that efficiently cleans the fatty and greasy air, so that it can be re-used. Theoretically we could therefore use our air circulation in a way that needs no more externally infused heating energy. Practically there is a little bit more to that. In fact, we still infuse 50 per cent of fresh air to our circulation system, otherwise the room would heat up too much.

2. Efficient provision of cold energy

We use the latest frequency-controlled, central cooling systems, that are running on their ideal capacity. Opposite to separately regulated single systems, a centrally regulated machine can cope with the challenge of cooling the entire area much better because instead of trying to adjust the single machines to work together, the central machine regulates the entire scope on its own. This uses less electricity and is more efficient because there are less singly working machines in the refrigerating plant.

3. Using the heat loss of cold energy

Of course, cold energy produces heat loss that would normally be emitted. Instead of wasting that inevitable heat, we make the most of it (during winter, we use 100 per cent; during summer, we capture it up to our buffer tank). Huge water tanks are connected to our refrigerating plant, that directly infuses the excess heat to those water tanks. On the one hand, this procedure is more efficient than emitting the excess heat into the air (water also has a higher heat transition coefficient than air), on the other hand, the (pre-)heated water is not only used for showers but also for dishwashers of our entire hotel. The hot water tank barely needs to be heated up externally. This saves our primary energy consumption.

4. Exchanging the electricity meter systems

We exchanged our electricity meter systems so that every 15 minutes the electricity is metered automatically. It is an “intelligent meter” so-to-say. For us this means that we can take immediate action when the meter reaches peak-times, so we can avoid those moments for the future. Without this automatic measuring, we could not have possibly learnt about the reasons for electricity consumptions that are higher than usual. With that information we can reduce our power consumption and detect “energy-gluttons”.

5. Intensive usage of LED-technology in the entire hotel

Due to our extensive restoration works, we could install LED-technology in our entire hotel area. So we were able to reduce the electricity consumption in the hotel rooms to only 20 per cent of the normal usage with normal lighting. And best of all: it also looks amazing.

6. Clearance of unnecessary power consumers

We installed motion sensors in our entire hotel, so that the lights are always automatically switched on when needed. Forgetting to switch off a light that is not needed, is a thing of the past. Plus, you do not need to search for a switch in complete darkness. What a comfort!

7. Insulation of all the heating and climate conduction

What sounds obvious, is not the case for most establishments. By exchanging the entire conduction system, we also installed a very efficient insulation for all conduits. After all, the energy is supposed to be used in heating or cooling, and not to get lost on the way there.

B. Insulation of the building after German law for economising energy consumption

The best energy is the one that is not consumed at all. Altogether the conservation of heating energy in our rehabilitated older building is approximately 50,000 kWh/year due to the combination of the following measures: insulation of our facade and roof truss plus draught proof, insulation of the in-between ceilings and the insulation of the flat roof in our adjoining room.

Because of reducing the rooms’ hypothermic, the system temperature of the heating in the whole house can be reduced, which helps saving energy. Because of the so-called hydraulic alignment of the radiator, individual rooms are prevented from overheating. The temperature in those rooms has also clearly improved. In addition to that, the air draught is not bothering the seating area any more.

A little story by the way: After completing the reconstruction work, we started to run our restaurant and hotel in summer 2015. After approximately 6 months a meterman came to read our electricity meter as a matter of routine. Two days later, we were visited by an unexpected “special force” of our electricity provider in order to have the meter checked once again. With a consumption of less than 15 per cent compared to the previous year, we were suspected to having abused the meter!

C. Optimisation of the energy supplier

We consciously decided to give up on energy through fossil fuels. As part of remediation measures we changed the energy supplier and are using the district heating grid of our local energy supplier. Because of the latest engineering concerning electricity and heating, our energy supplier contributes to saving energy and lowering the CO₂ emission.

D. Further steps

We are avoiding disposable package wherever possible. That is why you will not find a single flacon of shampoo in your bathroom. Instead, we are using the beauty products of the brand “Stop the Water while using me”, whose refilling is available in big containers.

We also give up on unnecessary rubbish in our FIVE Diner. We are cooking and refilling our self-made jam and we are also avoiding individual packaging. Apart from the ketchup we are freshly preparing all our burger sauces ourselves.

We are preferably buying our products from local suppliers. That does not only save the environment because of short transportation routes, but also strengthens the domestic economy.

All taps and shower heads are prepared with water saving efforts. Because of adding air to the water stream, we reduced water consumption to 4,5 litre of water per minute during showering. Furthermore, we are preparing our fresh water in a decalcifying plant. Thus we are reducing the washing amount and powder twice: first, because the shower gel and shampoo are foaming better in the warm, rehashed water. The surfactants of the shampoo do not have to generate lime, instead they can deal with the dirt that wants to be washed off. The user will adjust the amount of shampoo automatically. Second, the amount of detergents will be reduced indirectly. Less lime scale in the bathrooms reduce the usage of aggressive detergents. Our cleaning staff needs less cleaning agent when they brighten up the shower glass detachment.