Fermenter Cooling and Glycol Chiller Sizing

For each tank, $m=\rho_b V$ and $E_f=m x_s h_f$. Fermentation heat is an assumed symmetric triangle over the entered fermentation time, with peak $2E_f/t_f$ and integral $E_f$. This profile is derived here as an energy-conserving scheduling approximation, not a measured kinetic law.

Crash cooling follows a prescribed linear temperature ramp. Its sensible energy is $E_c=(m c_{p,b}+C_{shell})(T_f-T_c)$ and its sensible power is $E_c/t_c$. Ambient heat gain is $UA_a(T_a-T_b)$ throughout each occupied phase. Fermentation ends before crash begins. After holding, the tank is empty and contributes no load.

Tank $j$ starts at $(j-1)t_{gap}$. The calculator sums all tank loads plus the continuous auxiliary allowance. The timeline contains every phase boundary and fermentation peak, in addition to a regular grid. Actual clock values are sorted by their signed differences. Each interval contributes its two endpoint values, with the phase selected at the interval midpoint. Shared boundary times therefore appear twice to show the exact left and right load limits. No small time offsets or tolerance-based deduplication are used. The curves are linear within each interval, so trapezoidal integration conserves fermentation and sensible-cooling energy without smearing phase changes into ramps.

The chiller requirement is $(1+f_{margin})\max Q(t)$. This is required thermal capacity at the actual operating conditions, not electrical power or a warm-water nameplate rating. Reserve is not deducted from tank loads.

For well-mixed beer and flowing glycol, $\Delta T_{lm}=\Delta T_g/\ln[(T_b-T_g)/(T_b-T_g-\Delta T_g)]$. Both end approaches must be positive. Required jacket UA is the larger of peak-fermentation load divided by its LMTD and cold-end crash load divided by its LMTD. This includes ambient heat gain. Available jacket UA divided by required UA must be at least one to deliver the specified ramp. The jacket-limited minimum linear crash time is $E_c/(UA_j\Delta T_{lm,c}-Q_{ambient,c})$; it does not include a chiller or pump limit. A blank time means the jacket cannot maintain the cold setpoint.

Glycol volume flow is $Q/(\rho_g c_{p,g}\Delta T_g)$. The design header flow transports the selected thermal capacity; branch flow uses the worst single-tank load. These are heat-balance flows, not a hydraulic pump selection.

• All tanks have the same working volume, properties, UA and recipe, with one batch each and no refills. The displayed horizon ends after the last tank's cold hold.
• Beer is well mixed; density, specific heat and effective jacket conductance stay constant. The default 1,030 kg/m³ and 4.04 kJ/(kg·K) are illustrative effective wort properties; confirm recipe-specific values.
• The fermented-extract input is a true consumed mass fraction on initial wort mass. Apparent Plato attenuation is not the same quantity. CO₂ mass loss is not separately tracked; effective thermal properties approximate its small sensible-energy effect.
• The 587 kJ/kg default is the Ziemann Holvrieka brewery guideline, page 10. González-Hernández et al. (2024), attached manuscript page 15, report −101.28 kJ/mol glucose for anaerobic fermentation, about 562 kJ/kg released. These values describe different substrates and models; heat input is editable.
• The triangular fermentation profile, 4 W/K ambient UA, 400 W/K jacket UA, 50 kJ/K shell capacitance, 0.3 kW auxiliary load and 20% reserve are declared planning assumptions, not measured equipment ratings.
• Glycol properties 1,041.9 kg/m³ and 3.81 kJ/(kg·K) come from Dow LC 25 data, attached page 2, at −5 °C. They illustrate a diluted propylene-glycol mixture. No food-contact approval or product suitability is inferred.
• No refrigeration storage credit, chiller cycling, solar gain, latent heat, residual fermentation during crash or evaporation cooling is included. The entire auxiliary allowance is coincident and constant.

Use for preliminary thermal sizing of beer-like batches with the cellar at or above fermentation temperature and glycol return below the cold target. A jacket warning means the drawn temperature ramp is a requested duty that this jacket cannot deliver; the load chart is not an achieved-temperature simulation.

Use supplier data or a measured cooling test to establish effective jacket UA, particularly at cold temperature when natural convection can weaken. A single UA cannot resolve stratification, partial jacket coverage, fouling or local freezing. Confirm the beer freezing point and glycol freeze protection separately; fluid properties are not automatically adjusted when temperatures change.

The chiller must meet the reported thermal capacity at the actual glycol supply temperature, concentration, outdoor temperature and condenser conditions. Obtain a supplier performance curve. Pump head, valve authority, minimum evaporator flow, pipe sizing, redundancy, repeated production cycles and unequal tanks require further design. Installation work belongs to qualified refrigeration and electrical personnel.

Published-source limits: Ziemann's page 10 states 8.3 kg extract per hL and 587 kJ/kg, but also 4,573 kJ/hL; their product is 4,872 kJ/hL. The tool retains mass × enthalpy and does not fit the inconsistent subtotal. The separate 420 kJ/(hL·K) cooling guideline is used as a property benchmark. BV Thermal's worked sensible-cooling numbers validate that duty only; its separate Brix-based fermentation shortcut is not implemented. The glucose reference case checks normalization to a published molar heat, not the assumed fermentation-time profile.