SOKRATHERM - Fachartikel

Energy on the way

Since April 1st 1999 mobile CHP’s have been equally taxed with stationary systems. This marks an important step, giving a smart concept market chances.

It's been a long journey:
When the Gas- und Wasserversorgung Hiddenhausen (GWH) took over the open-air swimming pool from the municipality in 1994, with the perspective of a fundamental reorganisation, they also tested the charge of a CHP. Unfortunately the open-air swimming pool season – short in comparison, due to our latitude – does not permit the running time of at least 5.000 operating hours per year, which is necessary for the economical operation of a CHP. This dilemma formed the idea of a mobile CHP – during the summer an open-air swimming pool heating device, during the winter season a heat supply of the administration building of the GWH.

Local change within one hour possible?

SOKRATHERM answered, built a flexible 'CHP mobile', a compact aggregate with sound damming housing, integrated switchgear cabinet and special couplings, which is positioned on set on a car trailer. This configuration makes a change of the location possible within one hour.

In May 1995 the 'CHP mobile' was started up in the new arranged open-air swimming pool Hiddenhausen and supplied the nearby administration building of the GWH during the following winter. The module was designed in a highly sufficient way, taking over the basic heat load of both objects. For the ‘peak load service’ conventional boilers had been installed. The parallel produced electric power was directed to the respective supply of the swimming pool or administration building.

Amortization period four to five years

The concept worked: the module reached during the open-air swimming pool season circa 3.600 and in the administration building circa 2.500 operating hours. Altogether much more than the necessary operation time for an economic application. The savings in energy cost came close to 30.000 DM per year, resulting in a approx. amortization time of only four to five years. "But…!", because after the first heating season the customs office announced that, due to the oil tax law only stationary combustion engines can be exempted from the additional fuels tax (for both mineral oil and natural gas) the concept was meaningless. With this 30 years old regulation the legislator gave the stationary gas engines a taxational favour in opposite to vehicle engines. But this meant fatal consequences for the CHP mobile: After the GWH had to pay a high arrears of tax, they had to remove the wheel frame in presence of the customs officer and firmly fix the CHP with a steel console on the floor of the central heating installation of the open-air swimming pool. Beyond that the GWH had to commit itself to keep the CHP stationary. Contraventions would be punished like tax evasion. With the end of the mobility the economic efficiency of the system was also no longer given. Against this very unsatisfactory fact, in 1996 the CHP mobile was announced to be an excellent example for guiding possibility to distinguish the decrease of the consumption of fossil energy sources and was given the award of the German gas economy.

Stationary installation is no longer necessary

After SOKRATHERM pleaded for many years to change the abstruse situation, the 1st April 1999 marks the breakthrough: with the change of the oil tax law the condition of the stationary installation is abolished. For the managing director Hermann Meinhold a reason for slide optimism: "due to the change in law we can’t expect a substancial breakthrough for our CHP mobile, but we expect a noticeable increase of inquiries, because many projekts have now been made econmical"

To the technique of the CHP mobile

The compact module is equipped with a natural gas powered, water cooled asynchronous alternator. It supplies an electricperformance of 51 kW and a thermal output of 102 kW. The overall efficiency is 91,6%, according to the manufacturer. The engine is equipped with a three-way catalyst, which reduces
the exhaust gas emissions to less than 25% of the values, which are permitted by the "TA Luft"*). The whole vehicle measures about four meters in length and nearly three meters in high.

"Umwelt Magazin" No. 6/99,
Vogel Verlag und Druck GmbH & Co. KG