Participating company | Andechser Molkerei Scheitz GmbH |
Project location | Bavaria |
Industry | Organic dairy |
Technologies used | CCHP (1 MWel + 392 kW saturated steam), absorption cooling system (431 kW) with adiabatic re-cooling system, compressed air CHP unit, heat recovery, stratified charge storage (120 m³), ice storage silo for peaks in the cooling process |
Energy efficiency | 31% reduction of initial energy consumption |
CO2 savings | 1,846 t CO2e/yr |
Additional environmental protection effect | Drinking water savings of 25,000 m³/yr |
Investment | €2,385,000 |
Payback period | 2.1 years |
Funding programmes | The low-temperature absorption cooling system with adiabatic re-cooling was funded as a demonstration project by the Bavarian Ministry of Economic Affairs. |
Andechser Molkerei Scheitz GmbH operates an organic dairy factory in Andechs (Bavaria). Originally, all of its electricity was drawn from the public grid. Steam was generated via steam boilers, refrigeration via piston compressors and compressed air via screw compressors without heat recovery.
Since 2020, a CHP unit with an absorption cooling system and a compressed air CHP unit have been used in the dairy factory with the support of AGO GmbH. The plants are closely interlinked, and the waste heat is fully utilised to achieve the greatest possible reduction of energy consumption and CO2 emissions. The 413°C exhaust gas produced by the CHP unit is used to generate steam. The exhaust gas is cleaned using an oxidising catalytic converter before being fed into the boiler. In order to be able to meet the stricter emissions requirements set to come into effect in 2025, the housing and the installation location for the exhaust gas purification system, including the SCR catalytic converter that will then be required, have already been provided. The hot water from the motor cooling system is reheated via a second exhaust gas heat exchanger. This heat output is used by the absorption cooling system for the cooling process. The hot water that is produced by cooling the mixed gas cooler, and which is not used for the absorption cooling system, is reheated from just 60°C to over 90°C in the heat exchangers of a compressed air CHP unit. At this temperature, the hot water can be used to heat yoghurt and thus compensates for the previous method of hot water preparation using steam. The CCHP (combined cooling, heating and power) unit’s absorption cooling system reduces the amount of electricity consumed by the cooling process. Dry adiabatic re-cooling systems are used to re-cool the refrigerant in the absorption cooling system. Peaks in the cooling process are collected in ice storage silos.
Transferability
In principle, it is entirely possible to transfer this project to the food industry, especially dairy factories, breweries, meat processing and cold storage facilities.
Energy Efficiency Award 2021
Pictures: Andechser Molkerei Scheitz GmbH