Solar integration guidelines in chocolate/cacao/coffee production

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CLEANING

Cleaning of production halls and equipment

CIP.jpg Example how to integrate solar heat for cleaning in place installations (CIP) in Food and beverage companies.

Cleaning-in-Place (CIP) is a method for cleaning process plants without removing single components. Therefore different cleaning cycles (daily to weekly) can be applied. Based on the respective production section, the cleaning is done with cold or hot water. A CIP system consists of multiple recovery tanks for acid, caustic, fresh and hot water, circulation and dosing pumps, one or more heat exchangers, and some other peripherals. CIP systems have often an external heat exchanger, which heats up the various media to the required temperature before they are pumped to the plant components that have to be cleaned. Through a circulation loop, the individual recovery tanks can be heated.

CIP systems with external heat exchangers are suitable for the integration of solar heat. If there are longer periods between the cleaning phases, the recovery tanks can be preheated with a smaller sized solar heat exchanger. If the set temperature is not reached through this measure, the conventional heat exchanger can supply the remaining thermal energy.

Source: Schmitt, B., 2014. Integration of solar heating plants for supply of process heat in industrial companies (in German language), Dissertation University of Kassel, Shaker Verlag, Aachen, Germany.


Solar application for cleaning


DRYING

Solar application for drying


EVAPORATION AND DISTILLATION

Evaporation

Dealcoholization.jpg Example how to integrate solar heat for dealcoholization of beer.

Dealcoholization processes are necessary to meet the growingmarketfor non-alcoholic(<0.05% by volume) andlow-alcoholic beer (<0.5% by volume). In addition to arrested fermentation andreverse osmosis, there are also thermal processesto producenon-alcoholic beers. However, notall breweries producenon-alcoholic beer. Dealcoholization processes are often foundinlarge breweries. The installations areusually designed with relatively low production capacities to maintain long and constant operation times.

Typical installations used for thermaldealcoholizationare rectification columns,thin film- andfalling film evaporators.Rectification columnsandfalling film evaporatorsare usually designed in multi-stage. Based on the sensitive product characteristics, the evaporator is operated with slight vaccum (both, product andheating side). Thereby thedealcoholizationoccursat low temperatures. Usually saturated steam atabout 60 °C is used as heating medium.

A heating systemconsistingof aconventionalheatedstorage, asolar heat exchangeranda vacuum pump are required to assist the dealcoholization process with solar energy.As shown in Figure 9, solar heat is used to preheat the condensate return. In case of insufficient solar irradiation, the condensate temperature can be increased with the conventional heated storage. Due to the illustrated bypass it is possible to use solar heatalready for the start up the plant.

Source: Schmitt, B., 2014. Integration of solar heating plants for supply of process heat in industrial companies (in German language), Dissertation University of Kassel, Shaker Verlag, Aachen, Germany.


Solar application for evaporation and distillation


COOKING

Cooking and boiling

PL E IS scalding.jpg Example how to integrate solar heat for a scalding process in chicken slaughterhouses.The displayed scalding bath for chicken slaughtering is conventionally heated by direct steam injection. Based on water discharge by carcasses and evaporation losses a significant amount of fresh water is fed to the scalding bath, which can be preheated by solar energy. Possibly, this integration concept can be combined with PL_E_PM and PL_E_HB.
Wort boiling.jpg Example how to integrate solar heat for a wort boiling process in breweries.

Different wort boiling technologies are used within breweries. The figure illustratesa vacuum boiling technology. Therefore, the wort is stored within the whirlpool, heated by an external boiler (usually tube bundel HX) and fed into an expanison vessel where the evaporation takes places. Aftewr a defined time of running this cycle at atmospheric pressure vaccum is applied and external heating is not necessary any more.

For wort boiling processes with external boilers solar heat can be used to preheat the wort before entering the external HX as illustrated in the figure.

Source: Schmitt, B., 2014. Integration of solar heating plants for supply of process heat in industrial companies (in German language), Dissertation University of Kassel, Shaker Verlag, Aachen, Germany.


Solar application for cooking


COOLING PROCESSES

Cooling, chilling and cold stabilization

Solar Powered Refrigeration

Solar powered refrigeration systems capable of providing temperatures as low as -23°C have been demonstrated.


(Solar driven) ejector refrigeration System

Ejector or jet pump refrigeration is a thermally driven technology that has been used for cooling applications for many years. In their present state of development they have a much lower COP than vapour compression systems but offer advantages of simplicity and no moving parts. Their greatest advantage is their capability to produce refrigeration using waste heat or solar energy as a heat source at temperatures above 80°C. Applications in the food sector will be primarily in areas where waste heat is available to drive the ejector system. Such applications can be found in food processing factories where the ejector refrigeration system can be used for product and process cooling and transport refrigeration. Other possible application is in tri-generation where the ejector refrigeration system can be used in conjunction with combined heat and power systems to provide cooling.


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