Thermal Process Engineering for Brewers

Home , Heat transfer

10/24/2014 Basics in Theory and Practiceandin Basics Theory for Brewers Thermal Process Engineering Email: [email protected] Email: 7472 688 414 Phone: Krones Brewing &Process Technology FredScheer M Inc

2｜kronesThermal ProcessBeispieltext Engineering for Brewers

Table of Content

. Why is a Basic Knowledge important for Brewers?

. Necessary Basics of Thermodynamics

• Heat and Energy • Definition of Thermodynamic Parameters • Thermal Energy and Power • Heat Transfer • How can Brewers improve the k-value and the Heat Transfer?

. Practical Calculations in the Brewery

• Mashing • Wort Boiling • Wort Cooling with a Plate Heat Exchanger • Importance of Tank Insulation • Fermentation

. Final Remarks 10/24/2014 3｜kronesThermal ProcessBeispieltext Engineering for Brewers

Why is a Basic Knowledge important for Brewers?

. Heat exchange can be found everywhere in the brewery!

Heating up the mash and hold the temperature break

Wort boiling

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Why is a Basic Knowledge important for Brewers?

. Heat exchange can be found everywhere in the brewery!

Wort cooling

Heat transfer between a tank and its

environment (for instance brewing liquor) 10/24/2014 5｜kronesThermal ProcessBeispieltext Engineering for Brewers

Why is a Basic Knowledge important for Brewers?

. Heat exchange can be found everywhere in the brewery!

Fermentation and beer storage Flash pasteurization

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Why is a Basic Knowledge important for Brewers?

. Average heat/cooling consumption of a 83,000 bbl brewery (100,000 hl)

Heat consumption of the 22.5 kWh/bbl sales beer brewhouse:

Of that mashing (infusion): 3 kWh/bbl sales beer >50% of the total heat are consumed Of that boiling (10% total 13.5 kWh/bbl sales beer in the brewhouse! evaporation):

Heat consumption of the whole 44.1 kWh/bbl sales beer brewery:

Cooling consumption of the whole 7.7 kWh/bbl sales beer brewery:

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Why is a Basic Knowledge important for Brewers?

. Heating oil price development in the past

 The price for heating oil rose in the past and will be unstable in the future!

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Why is a Basic Knowledge important for Brewers?

• Heat transfer is part of many processes during beer production.

• The knowledge about the physics behind is important to ensure high product quality.

• It also offers the opportunity to improve your wort-/beer taste.

• Understanding heat transfer means recognizing potential to save money in the future.

• Saving primary energy means to be more independent of the uncertain development of heating oil prices.

• Additionally, CO2-Emission may be decreased.

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Table of Content

. Why is a Basic Knowledge important for Brewers?

. Necessary Basics of Thermodynamics

• Heat and Energy • Definition of Thermodynamic Parameters • Thermal Energy and Power • Heat Transfer • How can Brewers improve the k-value and the Heat Transfer?

. Practical Calculations in the Brewery

• Mashing • Wort Boiling • Wort Cooling with a Plate Heat Exchanger • Importance of Tank Insulation • Fermentation

. Final Remarks

10/24/2014 10｜kronesThermal Beispieltext Process Engineering for Brewers

Heat and Energy

. What is heat?

Heat (abbreviation ) is energy that is being transferred based on a temperature difference of a system and its environment (or between two systems) across the common system boarder . 푸

Heat comes from the higher temperature level to the lower temperature level. The results are often serious.

 Therefore, heat always flows from the system with a higher temperature level to the system with lower temperature level (according to the second law of thermodynamics).

 Heat flow ( )is determined as the transferred heat in a certain time interval. It can be considered the same as the thermal power. 푸̇ 10/24/2014 11｜kronesThermal Beispieltext Process Engineering for Brewers

Heat and Energy

. Heat is transferred energy. But how is energy defined? . Example: What contains more energy: a cup of hot soup or a glass of water?

. Obviously, the soup has got more energy because of its higher temperature.

 Energy is the ability of a system to work or to release heat.

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Definition of Thermodynamic Parameters

. Specific heat capacity (also called specific heat):

푝  The specific capacity푐 describes which quantity of heat is required to rise the temperature of 1 kg of a certain substance by 1 Kelvin. The physical unit is . The value only applies for a certain pressure. 푘푘 푘푘∙퐾 푐푝

Fluid [ ] for atmospheric pressure Specific heat value 푘푘 푝 Water 푐 푘푘∙퐾 4.18 Mash (15 °P) 3.73 Mash (20 °P) 3.60 Mash (25 °P) 3.46 Wort 4.0 – 4.1 Air 1.005

 With increasing density of the mashes, the specific heat decreases. 10/24/2014 13｜kronesThermal Beispieltext Process Engineering for Brewers

Definition of Thermodynamic Parameters

. Specific Enthalpy :

 Enthalpy meansℎ the content of heat of a body. The specific enthalpy is the heat in relation to mass [ ]. For fluids applies:

푘푘 푘푘 = : Temperature enthalpy = specific heat value X delta Temperature ℎ 푐푝 ∙ Δ푇 푇  Enthalpy of vaporization/-condensation [ ] is the content of heat that is required/released for changing the state of aggregation푘푘 from liquid to vapor state and 푟 푘푘 vice versa. The amount of enthalpy depends on the pressure level of the system (vapor pressure!). For condensing saturated steam applies:

= Pressure of the system [ ] for water/vapor transformation (abs.) 푘푘 ℎ 푟푘푘 1.0 푟 2,257.9

1.5 2,226.2

2.0 2,201.6 5.0 2,107.4

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Thermal Energy and Power

. How can you calculate the energy of a fluid? Specific Enthalpy

ℎ Generally: = : Mass of the material For fluids: = 푚 푄 푚 ∙ ℎ Specific heat capacity Saturated steam: = 푝 푄 푚 ∙ 푐 ∙ Δ푇 푐푝 푄Enthalpy푚 of∙ 푟vaporization/-condensation . The required thermal power can be found by considering the time to heat up a body/fluid: 푟

= : Time 푄 푡 Further examples concerning푄̇ brewing in a later chapter

푡

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Heat Transfer

. 3 possibilities of transferring heat through a vessel wall:

• Heat conduction

• Convection

• Heat radiation (not considered in this presentation, but in fact has influence on wort boiling and cooling outdoor fermentation tanks)

 In reality, there is always a combination of the three types.

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Heat Transfer

. Heat conduction and thermal conductivity λ Steam Wall Mash/wort („lambda“ ):

• Material property that describes how big the temperature difference between the λ in- and outside of a wall is. Temperature level Thermal wall 1 p[ower Temperature level • = λ ( ) 푊푊 wall 2 퐴 푇 ̇ 푊푊 푊푊 푄 ∙ 푠 ∙ 푇 − 푇 푇푊푊

Material λ[ ] for 68 °F 푾 Heat transfer Stainless Steel 풎∙푲15 area

Copper 380 퐴 Wall thickness Aluminum 229 푠 Silver 410

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Heat Transfer

. Convection Steam Wall

• The convection coefficient describes the ability of a fluid (gas) to gather / release energy from / to the surface휶 of a wall. Steam temperature • = ( ) 푇1 α1 Temperature level 푄̇ α1 ∙ 퐴 ∙ 푇1 − 푇푊1 wall 1 • (unit ) can be specified by 푊 푊푊 experiments 2using dimensionless numbers 푇 (eα .g. Reynold’s푚 ∙퐾 number). Heat transfer • α-value depends on: area  Material properties (of the wall and of Wall the fluid) 퐴 thickness  Fluid flow near the wall (higher turbulents result in better ) 푠

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Heat Transfer

. The real heat transfer: Steam Wall Mash/wort

• In real heating (and cooling!) processes, a combination of conductivity and convection takes place. ̇ • The whole heat transfer is characterized 푄λ by the k-value. Steam temp. α1

• = 푇1

1 푇푊푊 2 1 푠 1 Temperature gradient: α 푘 α1 + + α2 Mash temp. • = ( ) The driving force of heat λ transfer Heat transfer 푇푊2 2 area 푇 푄̇ 푘 ∙ 퐴 ∙ 푇1 − 푇2 • Conventional mash tuns obtain a k-value 퐴 Wall of 1,000 – 1,500 thickness 푊 2 푚 ∙퐾 푠  The k-value is a dimension that estimates

whether much or less heat is transferred

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How can Brewers improve the k-value and the Heat Transfer?

. Basically, the higher the turbulences in the product and the heating medium, the better the k-value

. Possibilities for higher turbulences:

• Proper agitation during mashing, including a fitting agitator shape (propeller mixer)

• Special surface of the mash tun/kettle  Pillow Plates, increasing the heat exchange area (k-value: 2,000 ) Flow profile

푊2 of an even • Using a circulation pump during boiling푚 ∙퐾 . surface

• Avoid fouling and calcification! Correct and proper cleaning of the tanks is important! Flow profile of a • Shape of the heating/cooling pipes. structured surface • Improved shape of the heat exchanger plates of the wort cooler or flash pasteurizer.

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Table of Content

. Why is a Basic Knowledge important for Brewers?

. Necessary Basics of Thermodynamics

• Heat and Energy • Definition of Thermodynamic Parameters • Thermal Energy and Power • Heat Transfer • How can Brewers improve the k-value and the Heat Transfer?

. Practical Calculations in the Brewery

• Mashing • Wort Boiling • Wort Cooling with a Plate Heat Exchanger • Importance of Tank Insulation • Fermentation

. Final Remarks

10/24/2014 22｜kronesThermal Beispieltext Process Engineering for Brewers

Mashing

. Assumptions

. Mash volume : 58 hl or 5,800 l

. Density of the 푉mash : 1.06 kg/l

푀 . Heat capacity of the mashρ : 3.6

푘푘 푝 . Mash-in temperature : 푐 333푘푘 K ∙퐾(140 °F)

. Transfer mash temperature푇푖푖 : 351 K (172 °F)

. Heat transfer losses : 푇표표표 5%

푙𝑙� . Heating rate : 푓 1 K/min Can be decreased by improving the k-value! 퐻퐻

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Mashing

. Which amount of heat is required?

. General equation: = . Considering mash: = 푄 푚 ∙ ℎ . Considering = = ( ) 푄 푚 ∙ 푐푝 ∙ Δ푇 . Considering = ( ) 푚 ρ ∙ 푉 푄 ρ푀 ∙ 푉 ∙ 푐푝 ∙ 푇표표표 − 푇푖푖

푓푙𝑙� 푄 ρ푀 ∙ 푉 ∙ 푐푝 ∙ 푇표표표 − 푇푖푖 ∙ 푓푙𝑙�

= = 1.06 5,800 3.6 351 333 1.05 = 418,310 푘푘= 116.2 푘푘 푄 ρ푀 ∙ 푉 ∙ 푐푝 ∙ 푇표표표 − 푇푖푖 ∙ 푓푙𝑙� 푙 ∙ 푙 ∙ 푘푘∙퐾 ∙ 퐾 − 퐾 ∙ Density of mash Heat capacity of mash Heat capacity of mash 푘푘 푘푘� Volume of mash

 This calculation applies for every infusion-mashing. For more precise calculation, you need to know your exact material data and you have to find out you transfer losses

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Mashing

. What amount of steam do you need to heat up the mash?

 The heat required from the mash must be served by the steam. Assuming we work with a saturated steam over pressure of 1 bar (equals 14.5 psi): Enthalpy of = condensation 2,206.1 kJ/kg = 푚푚�푚 푠�푠𝑠 푄 푄, = 푚푚�푚 = 푠�푠𝑠 1 푏=�푏189.6 steam 푄 푚, . ∙/푟 푄푚푚 �푚 418 310 푘푘 . The consideration for the푚 푠thermal�푠𝑠 �power1 푏�푏 during2 206 1 푘푘 heating푘푘 -up from푘푘 one rest to another are analog. Heat flow Heating rate Mass flow of saturated steam determines the = thermal power = (and vice versa) 푄̇푚푚�푚 푄̇푠�푠𝑠 1.06 5,800ρ푀 ∙ 푉3.∙6푐 푝 ∙ 퐻퐻 1푚̇ 푠�푠𝑠= ∙ 푟1 푏�푏 2,206.1

푘푘 369 푘푘 퐾 푠�푠𝑠 푘푘 ∙ = 푙 ∙ ∙ = 0.167푚 ̇ = 10∙ Density of 푙 2,206.1푘푘 ∙/퐾 60푠 푘푘 mash Specific heat 푘푘 푘푘 푘푘 capacity 푚̇ 푠�푠𝑠 푘푘 푘푘 푠 푚푚푚 10/24/2014 25｜kronesThermal Beispieltext Process Engineering for Brewers

Wort Boiling

. Example: External boiling: How often must the wort circulate to achieve the desired evaporation?

. Assumptions

• The technology ensures an evaporation rate of 6%/h

• Density water : 965 kg/m3 퐸 Density of wort at boiling-temperature. With 푊𝑊𝑊 increasing temperature, the density decreases. • Density wort ρ : 1,030 kg/m3 => Boiling-temperature means lower density

푊표�표 • Specific heat ρ , : 4.1 푘푘 • Temperature 푐difference푝 푊𝑊� between푘푘∙퐾 in- and outlet of the boiler: 5 K

• Enthalpy of evaporation Δ푇: 2,250 kJ/kg

푟

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Wort Boiling

. Example: External boiling: How often must the wort circulate to achieve the desired evaporation?

. The number of cycles is defined by the wort flow and the cast out wort

= 푤𝑤� 푉̇ � . The thermal power of boiling power푉 푐must𝑐� 표표표 be the same as the thermal power Density wort for evaporation. Heat capacity Heat flow = The evaporation rate always refers Must be , to the cast out wort the same! 푏𝑏𝑏푏 푤𝑤� 푊𝑊� 푝 푊𝑊� 푄̇ 푉̇ = ∙ ρ ∙ 푐 ∙ Δ푇 Enthalpy of condenstion

푄̇�푒𝑒𝑒𝑒𝑒� 푉푐𝑐� 표표표 ∙ 퐸 ∙ ρDensity푊𝑊𝑊 ∙ 푟 . Result: water 1 0.06 965 3 2,250 / 1 = = = 6.2 , 푘푘 퐸 ∙ ρ푊𝑊𝑊 ∙ 푟 1,030∙ 3 4.1∙ 푘푘5 푘푘 � ℎ 푚

푊𝑊� 푝 푊𝑊� ρ ∙ 푐 ∙ Δ푇 푘푘 푘푘 ℎ ∙ ∙ 퐾  7 cycles푚 per hour푘푘 ∙required!퐾 10/24/2014 27｜kronesThermal Beispieltext Process Engineering for Brewers

Wort Cooling

. While cooling down the wort, hot brewing liquor will be gained.

. For the configuration of a counter-flow plate exchanger, one has to consider the different temperatures of the water in different parts of the wort cooler.

Temperature 366 °K Inlet temperature of the wort

Outlet temperature of the wort 344Δ푇 °푚푚푚K

Outlet temperature of the 288.5 °K brewing liquor 275 °K InletΔ푇푙 temperature𝑙 of the brewing liquor Exchange area . For that purpose, the average logarithmic temperature is used for calculations:

= Δ푇푙𝑙 ( ) Δ푇푚푚푚−Δ푇푙푙푙 Δ푇 푙𝑙 푚푚푚 Δ푇 ln Δ푇푙푙푙 10/24/2014 28｜kronesThermal Beispieltext Process Engineering for Brewers

Wort Cooling

. Assumptions: . The wort gets chilled down from 200 to 60 °F (equals 366 to 288.5 K) . The brewing liquor’s temperature rises from 36 to 165 °F (275 to 344 K)

 = 366 344 = 22 . = = = 17.4  = 288.5 275 = 13.5 ( ) Δ푇ℎ푖𝑖 퐾 − 퐾 퐾 Δ푇ℎ푖푖( �−Δ푇푙푙푙) 22 퐾−1.3 5 퐾 푙𝑙 Δ푇ℎ푖푖� 22 퐾 Δ푇 ln ln 13 5 퐾 퐾 Δ푇푙𝑙 퐾 − 퐾 퐾 Δ푇푙푙푙 . Required thermal power: , ( , , ) Density wort = Heat capacity ρ푤𝑤� ∙ 푉푐𝑐� 표표표∙ 푐푝 푤𝑤� ∙ 푇푤𝑤� 푖푖𝑖� − 푇푤𝑤� 표표표𝑜표 푄̇ 1.03 5,800 4.1 (366 288.5 ) 푐푐푐𝑐𝑐 푡𝑡푡 = 푘푘 푘푘 = 527.3 ∙ 푙 ∙ 3,600 ∙ 퐾 − 퐾 푙 푘푘 ∙ 퐾 푘푘 푠 . How much brewing liquor can be gained? Thermal power 527.3 = = = 6,550 ( ) , ̇ 4.2 (344 275 ) 푤𝑤𝑤 푄 푘푘 푘푘 Heat푚̇ capacity 푝 푤𝑤𝑤 푤𝑤𝑤 표표표𝑜표 푤𝑤𝑤 푖푖𝑖� 푘푘 푐 ∙ 푡 − 푡 ∙ 퐾 − 퐾 ℎ = , 푘푘 ∙ 퐾

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Wort Cooling

. Which exchange area is needed? Required thermal power 527.3 = = = 10.1 2 3.0 17.4 푄̇ 2 푘푘 Delta T log slide 28 퐴 푚 푙𝑙 푘� 푘 ∙ Δ푇 ∙ 퐾 Given by supplier . In case that one plate has 0.4 2 exchange area:푚 ∙ 퐾

10.1 2 푚 = = 25.25 = 26 ! 0.4 2 푚 푁푁�푁𝑁 𝑜 푝�푝𝑝� 푝�푝𝑝� 푚

 Those equations apply for any single-stage plate heat exchanger! That means, for example, that a flash pasteurizer can be calculated the same way. A two-stage heat exchanger can also be calculated like this by using other material properties and temperatures.

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Importance of Tank Insulation

. Remember the situation of heat transfer through a wall (slide 19). . How does the situation change, when the tank wall is insulated?

Brewing Wall Air Brewing Wall + Air liquor liquor Insulation

Heat flow ̇ 푄λ Thermal 푄̇ Steam conductivity temp. 1 1 λ λ α 푇1 α 푇1 푤𝑤� 푖𝑖

α2 α2 Mash temp. Heat transfer Heat transfer 2 2 area 푇 area α 2 Wall 푇

Insulation 퐴 Wall 퐴 thickness thickness thickness

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Importance of Tank Insulation

. Without insulation:

1 1 = = = 12.16 1 1 1 0.03 1 2 + + + + � 푘 300 15 13 Convection 푠 2 푚 2 coefficient Thermal 푚 ∙ 퐾 α1conductivityλ α2 � � � . With insulation: 푚 ∙ 퐾 푚 ∙ 퐾 푚 ∙ 퐾

1 1 = = 1 1 1 0.03 0.1 1 + + + + + +

푘 300 15 0.05 13 푠푤𝑤� 푠푖𝑖 2 푚 푚 2 α1 λ푤𝑤� λ푖𝑖 α2 � � � � 푚 ∙ 퐾 푚 ∙ 퐾 푚 ∙ 퐾 푚 ∙ 퐾 = 0.48 2 � 푚 ∙ 퐾  About 25 times less heat loss due to insulation!

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Fermentation

. Basic knowledge about circulation in the fermentation tanks • Beer has its highest density at about 37 °F (3 °C)

• Due to different density-levels, there is a natural convection (circulation) in a fermentation tank

• So, what happens during primary fermentation (>37 °F) and maturation (<37 °F) in the tank?

72 °F The beer flow and the 30 °F position of the warmest/ coolest liquids change!

60 °F 35 °F

Above maximum-density Beneath maximum-density temperature temperature 10/24/2014 33｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

. During primary fermentation, the coolest liquid is at the bottom of the tank.

. During maturation, the warmest beer is at the bottom of the tank. Cool jacket for 1 storage  Cone jackets necessary! volume

. That fact is important to understand when the cooling jackets are switched on or off. Upper cool 2 jacket for . During primary fermentation, the upper cool fermentation jacket has to be switched on (area 2).

. When the green beer gets chilled to maturating Lower cool temperature, all cooling jackets have to be 3 jacket for activated (1+2+3+4) fermentation

. After reaching maturation temperature, cooling the cone is sufficient (4). 4 Cone jacket

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Fermentation

. Knowing the principles about cooling beer can prevent you from ice layers on fermentation tanks.

. Having thick ice layers does not mean your beer has got its must temperature.

. In fact, it is an evidence for erratic cooling and uneven temperature distribution is in the tank. Good idea

Bad idea . This results in quality deviations of the beer. The fermentation and the beer taste is unsatisfying.

. Furthermore, formation of ice layers means a too high consumption of energy.

. Other reasons for ice layer formation might be:

• Location of the cooling jackets

• Placement of the temperature probe

• False control of the flow of the coolant 10/24/2014 35｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

. Which refrigerating energy and power is required from the refrigerating plant?

. Assumptions for calculating:

• Fermentation and maturation temperatures.

• Real density of the wort in the beginning: 12 °P (12%) = 9% • Real density of the wort after fermentation: 3 °P (3%) Δ퐸 • Volume of green beer: 50 bbl

• Radiation and heat insertion from environment neglected.

• Material properties supposed ( , ρ)

푐푝 • = 587 푘푘 � 푘푘

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Fermentation

Temperature 1 2 3

68 °F

60 °F

34 °F 0.5 d 4 d 1 d

Time

1 No cooling energy required! During respiration and fermentation, yeast releases heat that helps to reach the primary fermentation temperature within a day.

2 Primary fermentation temperature is reached and fermentation heat has to be discharged. The yeast produces = 587 kJ per kg fermentable sugar.

� 3 Cooling down the green beer to maturation temperature determines the necessary power of the refrigerating plant. 10/24/2014 37｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

Temperature 1 2 3

68 °F

60 °F

34 °F 0.5 d 4 d 1 d

Time

1 No cooling energy required! During respiration and fermentation, yeast releases heat that helps to reach the primary fermentation temperature within a day.

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Fermentation

. Energy gained while heating up to primary fermentation temperature:

1 = , = 1.03 5800푸ퟏ 4흆.04풘풘풘풘 ∙ 푽 ∙ 풄풑 풘풘풘풘288.5∙ 푻풔�풔293𝒔 − 푻풇풇=𝒇풇풇108𝒇�풇�,607풇 = 30 푘푘 푘푘 Negative because that ∙ 푙 ∙ ∙ 퐾 − 퐾 − − 푘푘� 푙 푘푘 ∙ 퐾 is no energy we have to . Energy, that has to be discharged during primary fermentation: insert!

2 = = 1.03 5800 0.09 587 = 315,606 = 87.7 푘푘 푘푘 푸ퟐ 흆풘풘풘풘m ∙ 푽 ∙ 휟푬h∙ � ∙ 푙 ∙ ∙ 푘푘 푘푘� 푙 푘푘 . Energy needed to cool down to maturation temperature:

= , 3 = 1.03 5800푸� 흆풘풘풘풘4.04∙ 푽 ∙ 풄풑 풘풘풘풘293∙ 푻풇풇𝒇274풇풇𝒇� 풇�풇=−458푻풎,𝒎564풎𝒎𝒎𝒎 = 127.4 푘푘 푘푘 ∙ 푙 ∙ ∙ 퐾 − 퐾 푘푘 푘푘� 푙 푘푘 ∙ 퐾

 Note: In reality, the density and the specific heat would change during the whole process. But the differences are very small, so they can be ignored. The values can be

considered as constant. Additionally, we must not forget the temperature difference between the environment and the tank content during the real process! 10/24/2014 39｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

Temperature 1 2 3

68 °F

60 °F

34 °F 0.5 d 4 d 1 d

Time

2 Cooling down the green beer to maturation temperature determines the necessary power of the refrigerating plant.

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Fermentation

. Energy gained while heating up to primary fermentation temperature:

 Note: In reality, the density and the specific heat would change during the whole process. But the differences are very small, so they can be ignored. The values can be

considered as constant. Additionally, we must not forget the temperature difference between the environment and the tank content during the real process! 10/24/2014 41｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

Temperature 1 2 3

68 °F

60 °F

34 °F 0.5 d 4 d 1 d

Time

3 Cooling down the green beer to maturation temperature determines the necessary power of the refrigerating plant.

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Fermentation

. Energy gained while heating up to primary fermentation temperature:

 Note: In reality, the density and the specific heat would change during the whole process. But the differences are very small, so they can be ignored. The values can be

considered as constant. Additionally, we must not forget the temperature difference between the environment and the tank content during the real process! 10/24/2014 43｜kronesThermal Beispieltext Process Engineering for Brewers

Fermentation

. Combining the three equations delivers the total amount of cooling energy:

= + + = 30 + 87.7 + 127.4 = 185.1 𝑡𝑡� 1 2 3 푄 푄 푄 푄 − 푘푘� 푘푘� 푘푘� . The required refrigeration power is determined푘푘 by �maturation temperature and the desired time to reach this temperature.

127.4 = = = 5.3 3 24 푄 푘푘� 푄̇𝑟푟𝑟𝑟𝑟𝑟𝑟 푘푘 . Assuming we use direct vaporization to푡 𝑡cool푡 the fermenter,ℎ which amount of ammonia do we need? (Using indirect cooling with water: same calculation as shown in section “Mashing”)

5.3 = = = = 0.004 = 푄̇𝑟푟𝑟𝑟𝑟𝑟𝑟 1,300푘푘 푘푘 ̇𝑟푟𝑟𝑟𝑟𝑟𝑟 𝑎𝑎𝑎� 𝑎𝑎𝑎� 𝑎𝑎𝑎� 푄 푚̇ ∙ 푟 ⇒ 푚̇ 𝑎𝑎𝑎� 14.7 / 푟 푘푘 푠

 Note: The calculations were made for ONE fermentation tank. If there푘푘 are more tanks that have to be cooled down at once you푘푘 ℎneed times more refrigeration power and

ammonia flow. 10/24/2014 44｜kronesThermal Beispieltext Process Engineering for Brewers

Table of Content

. Why is a Basic Knowledge important for Brewers?

. Necessary Basics of Thermodynamics

• Heat and Energy • Definition of Thermodynamic Parameters • Thermal Energy and Power • Heat Transfer • How can Brewers improve the k-value and the Heat Transfer?

. Practical Calculations in the Brewery

• Mashing • Wort Boiling • Wort Cooling with a Plate Heat Exchanger • Importance of Tank Insulation • Fermentation

. Final Remarks

10/24/2014 45｜kronesThermal Beispieltext Process Engineering for Brewers

Final Remarks

. As we can find heat transfer everywhere in the brewery, brewers should know about the basics of thermodynamics.

. Those basics lead to equations to calculate the required heat/cold and thermal power of a process.

. That not only helps you to appraise energy consumption, but also to recognize potential for savings.

. We discussed practical applications for the main operations during the brewing process.

. The calculations should not be seen as total but they give you a close idea in which regions you operate. Include a safety factor in your calculations (5-10%)!

10/24/2014 10/24/2014 Thanks for your attention!