Difference between revisions of "Handbook"

Revision as of 13:03, 12 May 2015

THIS HANDBOOK IS STILL IN PROGRESS

General Description of Tool

Working with the GREENFOODS branch concept

Download and Start the GREENFOODS branch concept

You can download the GF BC from the homepage of the GREENFOODS project green-foods.eu and from the national VECC (listed in Annex). The GF BC is an Excel Tool. There is now need to ‘install’ the tool. Make sure you save the file in a directory where you do not need administrator rights. Open the GF BC with an ordinary double-click on the file. You may need to activate the contents or allow macros to be activated. You will see following screen. Start the GF BC with a click on the green error.

Selection a Branch in the GREENFOODS branch concept

You may select any of the 5 branches in the GF BC.

File:Fig branchconcept branch.png

Once you select a branch you are immediately forced to save the Excel-File as a new version.

After this initial saving process you will have two versions of the GF BC:

• Version 1: The original version. It is now closed. No branch is selected. It can be used for new projects.
• Version 2: The current version. It is now open. A branch is selected which cannot be changed in this version.

Effects of the branch selections

• The general input form will be individualized to the selected branch
• The benchmark data is individualized to the selected branch
• The relevant processes are activated for the selected branch
• WikiWeb information (buttons) are individualized

Defining the Status Quo - Energy Balancing in the GREENFOODS branch concept

General Imput

In the general input section some basic data must be entered:

• Ambient Conditions
• Country
• Company Data
• Water Input
• Material Input (branch specific)
• Energy Input --> Linked to the Energy Flow Sheet

At least one product must be defined in the “material input” section:

→

Energy Imput

In the GREENFOODS branch concept, 10 energy sources can be selected and a 11th added by the user with individual configurations.

Processes

process xy

Description of process

Method of calculating energy demand

Formula to determine energy demand

Embedding in branch concept

Baking Oven

Description of process

The baking process transforms an unpalatable dough into a light, readily digestible, porous flavourful product. The physical activities involved in this conversion are complex but the fundamentals of these are explained here: Information about bread The internal loaf temperature increases to reach approximately 98°C. The loaf is not completely baked until this internal temperature is reached. Weight is lost by evaporation of moisture and alcohol from the crust and interior of the loaf. Steam is produced because the loaf surface reaches 100°C+. As the moisture is driven off, the crust heats up and eventually reaches the same temperature as the oven.

Method of calculating energy demand

The unit operation “baking” is related to the drying operation. The process involves the evaporation of water in the dough which is known as the baking loss.

The baking loss is the ratio between water loss during baking and dough input.

Additionally, at the beginning of the baking process steam is supplied to the baking oven for better heat conductivity of the baking goods. If the required steam is generated by the baking oven itself (e.g. internal electrical steam generator) then the necessary energy demand is calculated. If, however, steam is supplied directly from a stream distribution line, then the respective amount of energy must be assigned in the energy supply section. The heating of the cold dough is also considered in the energy demand. File:Fig processes bakingoven.png

For the startup of the oven only the heating of the air is considered, but not the heating of oven-material. Heat losses are comprised of radiative and conductive heat losses.

Formula to determine energy demand

Where:

Embedding in branch concept

• The total dough input of 4 baking goods can be defined in the “General Input” form. The definition of the baking loss is also defined there.
• The energy supply is likely to come from different sources (e.g. thermo-oil for baking power, steam inlet for steaming, electricity for lighting)
• The usage of the remaining vapors (from the steaming) for heat recovery is a key energy efficiency measure in bakeries. The condensation enthalpy of the steam is added to the pinch stream list. Currently, only the condensation enthalpy at 100°C is considered in pinch analysis.

Pasteurization

Description of process

Pasteurisation is a controlled heating process used to eliminate any dangerous pathogens that may be present in milk, fruit-based drinks, some meat products, and other foods which are commonly subjected to this treatment. Pasteurization inactivates most viable vegetative forms of micro-organisms but not heat-resistant spores. As well as the application to inactivate bacteria, pasteurization may be considered in relation to enzymes present in the food, which can be inactivated by heat (BAT in the Food, Drink and Milk Industries, June 2005) Pasteurisation is used to treat all types of food products. These include milk, juices, beer and many others. [[1]]

Method of calculating energy demand

In order to calculate the energy demand of pasteurization, the user has 4 options:

• Batch process with no internal heat exchanger
• Continuous process with no internal heat exchanger
• Batch process with internal heat exchanger
• Continuous process with internal heat exchanger

Energy is needed to heat up the medium to the pasteurization temperature and hold it for several seconds or minutes.

Formula to determine energy demand

Embedding in branch concept

• For heat recovery the heating of the product is added as a pinch stream (if there is already an internal heat exchanger the remaining heat demand is added). Similarly, the cooling of the product after pasteurization is also added as a pinch stream.
• All available energy sources can supply to this process
• Additional information on emerging technologies in this area is available in the WikiWeb.

Space Heating and Cooling

Description of process

Production halls and offices have to be heated and increasingly commonly cooled. Space heating and cooling can be done by ordinary radiators, surface heating or ceiling spots. The equipment are supplied with a hot medium, some may be driven electrically. Heating and cooling of production halls and offices can have a high share of the energy demand in less energy intensive production facilities. It can be an important heat sink for waste heat integration.

Method of calculating energy demand

In order to determine the energy demand for heating and cooling the production facilities and offices the area [m²] and specific heating/cooling demand [kWh/m².a] can be entered. Additionally, heating/cooling hours as well as supply and return temperatures are defined so the data can be used as heat sinks and sources in the heat integration analysis.

File:Fig processes space define.png

Multiple areas can be defined which have heating and/or cooling demand. The areas are listed in a heating and a cooling section and can be edited or deleted anytime.

File:Fig processes space areas.png

The “total space heating demand” and the “total space cooling demand” require a connection with an energy supply from the distribution list. It is possible to define 3 energy supplies. If both heating and cooling takes place then at least one “heating source” and one “cooling source” must be assigned, additionally a third source (either heating or cooling) may be selected.

Formula to determine energy demand

Where:

Embedding in branch concept

• The energy supply may be split into heating and cooling sources
• Space heating is an important heat sink for heat recovery measures in many cases. It is added as a cold stream in the heat recovery analysis. The extracted heat from cooled spaces can technically serves as heat source for heat recovery or heat pumps, but it is not likely to be actually used. However, it is still included in the stream list as hot stream.

Optimisation

System Optimisation

For the system optimization of the company under investigation the GREENFOODS BC has incorporated a Pinch Analysis, which is a methodical approach of identifying heat recovery potentials and setting up a heat recovery network. For Pinch Analysis it is necessary to retrieve all possible thermal energy streams that must be either heated up (=cold streams) or can/must be cooled down (=hot streams). The summary of this streams is called the pinch stream list. There are 2 ways to get the data for the pinch stream list:

• The GF BC automatically retrieves the data of hot and cold streams from the process and utility definitions while setting up the energy balance of the status quo.
• In the Pinch Analysis Form, the user can add extra streams that are not considered in the energy balance before.

File:Fig optimisation SystemOptimisation PinchAnalysis.png

Via vectorial addition, all hot streams are combined to the “hot composite curve” = (HCC) and all cold streams are combined to the “cold composite curve” = (CCC).

It is important to note that the Pinch Curves show only the process and extra streams but not the utility streams.

The Grand Composite Curves gives better insights in the placement of utilities and the actual required temperature level of the processes.

Integration of Renewables

Solar Thermal Heat for Industrial Processes

Photovoltaic

Biogas

Biogas is an important potential for renewable energy production in the food and drink industry.

Details on biogas production: [2]

Step 1: Biogas Sources

There are 2 different types of biogas sources: Option 1: waste water

For more information see: [3]

Option 2: residue streams

See also Table 8 in following link: [4]

Step 2: Biogas Utilization

Biomass CHP

Heat Pump

The heat pump module helps us decide if to use a heat pump to lift the temperature of a heat flow to heat up another heat flow. A low temperature waste heat flow can be upgraded to useful high temperature heat with the use of a heat pump. The mechanical heat pump type is the most commonly used. Its principle is based on compression and expansion of a refrigerant. For large scale industrial applications, Ammonia is the most suitable refrigerant for heat pumps that deliver heat up to a temperature of 90 °C. Ammonia is considered to be one of the most efficient refrigerants. However its use comes with certain safety measures. Therefore Ammonia is mainly used for large industrial installations. The choice of refrigerant for a certain application is determined by the temperature range of its thermodynamic cycle and the size of the installation needed. Refrigerants can be divided into two groups: natural refrigerants (Butane, Ammonia, CO2) and synthetic refrigerants (R134A, R407C, R410A). For commercial applications synthetic refrigerants are favoured over natural ones. A disadvantage of synthetic refrigerants is their strong contribution to the greenhouse effect in case of leakage. The negative impact of synthetic refrigerants is, for example, 1300-2100 times higher compared to CO2. In this tool, we will analyze 3 refrigerants: Ammonia (R717), R134 and CO2 (R744). Although new refrigerants are starting to be used with good performances (R245a), they are still not widely spread, and thus we will limit ourselves in the tool to the three forementioned. The tool will allow the introduction of new refrigerants, either transcritical or non-transcritical.

The analysis of the potential of the heat pump in the tool is done using a userform that recovers the data from the different energy flows.

In the left part of the screen, the 1) heat sink (where we will get the heat from) and the 2) heat source (where we will send the heat to) must be selected from the combo lists. In 3) , we will introduce the percentage of hours where the heat sink and the heat source are operating at the same time. If no simultaneity exists between the flows, the number must be 0. If complete simultaneity exists, It must be 100. In point 4), a first analysis, based on real life installations (more references in Wiki Heat Pump Costs) is done, to evaluate for the given processes which is the most interesting heat pump refrigerant. Two optimization indicators can be used, either maximum energy recovery or optimum payback. Once we have seen the results, we select a refrigerant, and the calculation is done, to evaluate the COP, the energy recovery and, given the investment costs we introduce, a payback. Limits are established as for temperatures .

• R717 and R134 cannot go higher than 90ºC
• For CO2 heat pumps, for a high temperature lift at the side of the gascooler (at least 30-40 °C) and a low temperature of the water that needs to be heated, the efficiency of a CO2 transcritical heat pump can be higher than conventional heat pumps. If the return temperature is higher than 30ºC, it cannot be used.

Results