When building a new Logistics centre, companies have a lot of opportunities to build cost effective and energy efficient buildings. The reasons for erecting energy efficient Logistics buildings are diverse. A Miebach survey gives you some orientation: The Miebach Consulting research team realized that even today the overall energy consumption of a Logistics centre can be covered by renewable energies. This result in a complete change, the distribution centre converts from an energy consumer towards a power plant. Today in times of relatively cheap energy, the main motivation for building green is less to save energy consumption but to cope with regulations, laws and to be independent from fossil fuels. Next to that, the image factor plays an important role as well at the moment. In the medium to long term, increasing energy cost will become more and more important for the profitability of the company.

 

What is the status quo? The energy costs for a conventional Logistics building are aprox. 80 Eurocent per square meter per month (2007 figures), with an average energy consumption of 8 kilowatt hours (kWh) per square meter per month. Half of the costs, our survey showed, are caused by the consumption of electricity, the other half is caused by heating expenses. A modern energy efficient Logistics centre needs to be energy efficient in the structure, the building installations and a very important point to take into consideration, the material handling equipment. The heating demand for an average Logistics centre is approx. half a litre of oil per square meter a month.

 

Due to the linked Oil and Gas prices (at least in Germany) the running costs for heating are levelling each other. A true alternative heating system, what isn’t connected to fossil energy prices is the heat pump. A heat pump driven with geothermal energy needs only a third of the energy consumed by a conventional heating system (measured in kWh). Only one part of electrical energy is needed to get up to 3 parts of thermal energy out of the ground. A positive side effect of the heat pump is the chilling mode. When changing the operation mode of the heat pump, a deep freeze storage can also be realized. The working principle of a heat pump is similar to a conventional refrigerator, with this principle cooling and heating is possible. Using the Earth as a heat source/sink, a series of pipes, commonly called a "loop," is buried in the ground near the building that needs to be conditioned. The loop can be buried either vertically or horizontally. It circulates a fluid (water, or a mixture of water and antifreeze elements) that absorbs heat from, or relinquishes heat to the surrounding soil, depending on whether the ambient air is colder or warmer than the soil. The heating of a warehouse via a heat pump should be realized with a panel heating due to the lower temperatures of the circulating fluid, a punctual conventional heating system demands higher temperatures and would use more energy.    

 

The following calculation shows the competitiveness of a geothermal heating system compared with a conventional heating system for a 15000 square meter Logistics centre. The heating demand for a logistics centre of this size is approximately 676 Megawatt. A heat pump system for this size costs around 600000 Euro more than a conventional heating system using fossil fuel. In operation this system would save about 57000 Euros a year due to the shown working principle. The return of investment is around 10 years in this case (Source: Zent-Frenger GmbH). It has to be checked for each case if this alternative is an economic one. With no doubt this modern heating system would boost the image of the company and presents a precaution against rising prices for fossil fuels.  

 

Due to the fact that electrical energy per kWh is 50% more expensive than the same amount of heat energy, the electrical consumption of a warehouse has to be considered despite the smaller share of electrical energy consumed compared with the total energy demand of the warehouse, Electrical energy is needed for lighting, IT, motors, drives, forklift trucks and conveyors. Additional to this a modern heat pump consumes electrical energy as well. The generation of sustainable electrical energy is possible. Wind energy, water power as well as solar energy can be converted to electrical energy even in a logistics distribution centre. The most common way of producing sustainable electrical energy is to use the plain roofs of the logistics building to install photovoltaic modules. Next to that a southward headed front of the building can be equipped with modules as well. Photovoltaic is the process of direct conversion of sunlight into electricity. For the production of 1 kW solar electricity a space of 9 square meters is needed (depending on the effectiveness factor of the module). The modules should be installed shadow free and orthogonal to the sun (this results in an angle of 20-35° in Germany). With this installation 1 kw installed photovoltaic modules can produce 800 kWh annually. The renewable energy law of Germany allows to sell the solar electricity up to 43,01 eurocent (price depends on the size and the year of installation). The investment of a photovoltaic system is around 3150 € per kW peak. When using 20.000 square meters with a PV System, an investment of 7 m Euro with a return of 750.000 € annually would cover the electrical demand of the logistic installation.

 

The energy costs is next only to the production on the efficient use of energy. All kind of energy has to be used efficiently. Precautions have to be taken, in order to not waste energy in the logistics centre, the loss of energy has to be reduced or completely avoided.  

 

The loss of heat (or cold) at the goods in/ out docks has to be reduced. Special gates for the docks with excellent insulation as well as an inflatable sealing can reduce the loss of energy through this opening. Next to that, an intelligent steering mechanism and a high speed closing opening mechanism can save further energy.

 

Insulation, as mentioned in the example above, can reduce the total energy consumption of the warehouse. The right choice of materials for the roof and the walls as well as the “right” choice for lighting will reduce the energy demand dramatically. When planning a logistics building the use of daylight for the lighting and heating should be considered. The remaining demand for light should be covered with energy efficient lighting systems and energy saving lamps. Modern lamps consume 65 to 80 % less electricity compared to conventional lamps.

 

Further hidden electricity consumers are conveyors and electrical driven forklift trucks. The electricity consumption of these devices have to be considered and the producers chosen accordingly. Energy saving potential can be realized with energy retrieving brake systems, intelligent steering, standby modes and a consequent Green IT strategy. Last but not the least: all processes in the warehouse should be highly efficient to avoid waste of energy. 

 

  

The author: Dr. Wolfram Süssenguth, Executive of the Miebach Consulting GmbH, Berlin and Frankfurt/Main   Contact: suessenguth@miebach.com; www.miebach.com