Cooling Systems for Mushroom Farming: Chiller Selection for Compost, Incubation, and Fruiting
Refrigeration Equipment and Chillers for Mushroom Farms
Modern mushroom farming is a high-tech process where each stage demands precise microclimate control. Efficient refrigeration systems and properly selected chillers are the foundation for stable yields, energy efficiency, and high product quality. Using button mushrooms as an example, we will explore how cultivation requirements impact cooling system selection — and why thoughtful equipment choice is critical for mushroom operations.
1. Application of Refrigeration Equipment in Mushroom Farming
Mushroom cultivation consists of several stages, each with its own temperature, humidity, and ventilation requirements. For a full picture, let’s briefly touch on compost production as well.
Even before the mushrooms are grown, specialized facilities produce the substrate in which the mycelium will later develop. The nutrient medium is made from organic waste (straw, chicken or horse manure, gypsum). The compost is fermented at high temperatures (up to 70 °C) and then pasteurized with steam to eliminate pathogens. After pasteurization, the compost must be rapidly cooled to 25–28 °C. This is known as “Phase 2” compost — a substrate ready for inoculation.
The same facility can also carry out inoculation of mycelium into the compost, followed by packaging and partial or full colonization. This is known as “Phase 3” compost, or “spawned compost.” Transferring inoculation to the substrate supplier is becoming more common, as it shortens cultivation cycles and increases production turnover at the farm.
However, inoculated substrate begins an active biological process — comparable to starting an engine — with heat generation and rising internal temperature. If the substrate temperature exceeds 27 °C, mycelium growth slows and competition from green molds intensifies. At 29–30 °C, colonization stops; if overheating continues, the mycelium dies.
Since transport from the supplier to the farm may take time, substrate can reach critical temperatures en route. That’s why it is essential to have a chiller with enough cooling reserve to rapidly bring the compost down to safe temperatures upon arrival.
Figure 1 shows the full mushroom cultivation cycle starting from incubation, with optimal climate parameters for each phase. If you’re using pre-colonized compost, simply locate the corresponding day on the graph from the start of incubation.
Cultivation Phases
- Mycelium Growth (Incubation)
For 2–3 weeks (depending on the method), the chamber maintains a temperature of 24–27 °C and relative humidity of 90–95%. During this period, the compost emits a significant amount of metabolic heat, which must be continuously removed using a chiller and HVAC system. - Fruiting Body Formation and Fruiting
After incubation, mushroom fruiting is triggered through a technique known as a “shock.” The chamber temperature is gradually lowered over 5 days to 18–20 °C, CO₂ levels are reduced (optimal: 0.1–0.5%), and humidity is increased. Even cold air distribution becomes critical here to avoid hot or dry spots that could affect mushroom development.
Harvesting and Cold Storage
Mushrooms grow rapidly and require manual harvesting. Within 1–2 hours after picking, the crop must be cooled to 1–2 °C — essential to preserve freshness and appearance. There are typically three harvest waves. Cooling and storage chambers are usually equipped with additional refrigeration systems. To maintain 1 °C in the chamber, the evaporator temperature must be set to around –6 °C.
Figure 1. Mushroom cultivation climate profile
The black line indicates the optimal compost temperature throughout the full growth cycle. The dotted line represents ambient air temperature, closely following compost temperature. Black dots indicate required water input — each dot equals 1 L/m², showing exact watering days for optimal yield. The two grey lines illustrate target values for relative humidity (solid) and CO₂ level (dashed).
(Source: Hollander Spawn, 2017)
2. What refrigeration equipment is suitable for mushroom production
2.1 Chiller
The core component of the cooling system is the integrated refrigeration unit for chilling the secondary coolant — the chiller. Most commonly used is an air-cooled chiller without a built-in hydromodule, as shown in Figure 2.
Figure 2. LENNOX NAC 300D NM7M 308 kW air-cooled chiller without hydromodule
These chillers are typically equipped with semi-hermetic or scroll compressors, air-cooled condensers, and axial EC fans.
Air-Cooled Condensers
Pros:
- Wide range of models from various manufacturers
- Lower capital investment
- Simple maintenance: no water pumps, heat exchangers, or water circuits on the condenser side
Cons:
- Higher condensing temperature: ~45 °C at +35 °C ambient
- Lower EER (energy efficiency ratio), especially during summer
Water-Cooled Condensers (Shell-and-Tube or Plate Type)
Pros:
- When paired with an open cooling tower, condensing temperature can be reduced to ~35 °C
- Energy efficiency improvement of 15–20% over air cooling
- Can be installed indoors (cleanroom, basement, etc.)
- Centralized condenser cooling (one loop for multiple chillers)
Cons:
- Higher cost: requires cooling tower, pump station, water treatment, chemical dosing
- More components: heat exchangers, filters, water treatment systems
- Regular maintenance needed (cleaning, disinfection, circulation system control)
Microchannel Aluminum Heat Exchangers (MCHE)
Pros:
- Reduces unit weight by 10–15%
- Smaller refrigerant charge — cost-effective for high-GWP refrigerants like R410A, R32, R454B
- Compact: enables smaller footprint or increased power in the same size
Cons:
- Not repairable locally: a leak requires full section replacement
- Sensitive to contamination
- Not compatible with aggressive cleaning agents
Integrated Hydromodule
Pros:
- Space-saving compact design
- Factory-assembled — fewer on-site works
- Quick commissioning
Cons:
- Limited pump parameters (flow, head, control)
- Difficult service access
- Lower flexibility for upgrades (e.g., adding frequency drives, bypasses)
Standalone Hydromodule
Pros:
- Custom pump selection by flow and pressure
- Easy service access
- Can be placed away from the chiller
- Easy to upgrade with expansion tanks, VFDs, flow meters
Cons:
- Requires more installation space
- More labor-intensive piping and installation
Refrigerant Selection
This is increasingly important given the tightening regulations on HFCs (hydrofluorocarbons) in the EU and Ukraine. Equipment using R410A and R134a is still available, but sourcing these refrigerants will become more difficult.
R410A (GWP = 2088)
- Status: Being phased out
- Regulation: Banned in EU for new split systems <12 kW from 2025. Rare in new EU equipment. Ukraine is also phasing out high-GWP refrigerants.
- Alternatives: R32 (GWP = 675), R454B, R466A
- Why still used: High energy efficiency, especially in HVAC and heat pumps, although it requires reinforced compressors and exchangers due to high pressure
R134a (GWP = 1430)
- Status: Gradually restricted
- Regulation: Banned in new EU car A/C systems since 2017; use in other sectors limited by quotas
- Alternatives: R513A, R1234yf, R450A
- Why still used: Lower efficiency than R410A, but operates at lower pressures — less demanding on equipment
2.2 Ventilation and Air Conditioning System
Maintaining a stable microclimate in the cultivation chamber is achieved via a dedicated ventilation and air conditioning system.
Figure 3 shows a typical layout, including:
- Heating section (calorifier)
- Cooling section (air cooler)
- Fine air filter
- High-pressure fan
During the summer period, air cooling is carried out via heat exchange with a secondary coolant supplied by the chiller (typically at +7 °C inlet / +12 °C outlet).
A typical air cooler delivers 15–30 kW of cooling capacity per heat exchanger block.
In winter, the heating section prevents overcooling of the chamber air. Heat sources may include:
- Electric heating element (TEN) — e.g., 9–15 kW per chamber
- Chiller with heat pump function (COP in heating mode ~3.0–3.5), offering an energy-efficient solution for heating
Figure 3. Air conditioning system for mushroom cultivation chamber
2.3 Air Distribution System
To ensure uniform temperature and humidity across the chamber, a system of flexible air ducts is used — as shown in Figure 4.
In this example, the ducts are made from plastic, 550 mm in diameter, with evenly distributed top and bottom perforations (10–15 mm in diameter).
The system includes:
- Two supply ducts mounted along the ceiling, 0.3 m below it, providing steady airflow velocity (0.3–0.5 m/s is optimal at bed level for uniform CO₂, heat, and moisture distribution)
- Three return ducts — one central and two lateral — channel exhaust air into the recirculation or extraction zone
Each duct is aligned with the aisles between mushroom beds, ensuring:
- Active heat exchange with compost and soil
- Prevention of hot or stagnant zones
- Temperature and humidity uniformity across the chamber within ±1 °C
Figure 4. Air distribution system in a mushroom cultivation chamber
3. How to Select a Chiller for a Mushroom Farm
The main parameter when selecting a chiller is its cooling capacity, which must compensate for the total thermal load of the cultivation chamber. The following heat sources are considered when calculating the thermal load:
- Through the building envelope (~40 W/m² of chamber surface)
- Ventilation fresh air intake (~100 W per ton of compost)
- Metabolic heat from colonized substrate (phase 3) (~1160 W/ton of substrate)
- Metabolic heat from pasteurized compost (phase 2) (~1500–1600 W/ton of substrate)
- Respiration of fruiting bodies (~300 W/ton of substrate)
- Infiltration through doors (depends on opening time — often underestimated; we recommend PVC strip curtains, especially for storage chambers)
- Heat generated by personnel (~200 W/person)
- Lighting (~5 W/m² of chamber)
- Additional equipment and fans in the chamber
It’s important to note that these loads do not occur simultaneously. For instance:
- The most intense compost heating occurs during active mycelium colonization, when the chamber is sealed, with no ventilation or personnel.
- In contrast, during the fruiting phase, ventilation and infiltration loads increase, but compost metabolic heat decreases.
Due to the complex and variable nature of thermal loads, an empirical rule is often applied in practice:
1.5–2.0 kW of cooling capacity per 1 ton of compost.
Thus, a chamber with 20 tons of compost requires a chiller rated at 30–40 kW.
If the farm uses multiple chambers with phase-shifted cultivation cycles, a diversity (simultaneity) factor of 0.5–1.0 can be applied.
This allows accurate system sizing without overestimation.
For an initial assessment, we recommend using our cooling capacity calculator, or contact us directly for a tailored recommendation based on your production specifics and cooling needs. We’ll help you choose a system that’s efficient and cost-effective.
Why Choose Equipment from EVROPROM
- Supply of inspected chillers from top brands
- Refurbishment and testing at our in-house facility
- Individual selection tailored to mushroom production needs
- In-stock units — fast delivery across Europe and beyond
- Warranties for used and outlet chillers
EVROPROM Reference List: How We Support Mushroom Producers
SVIT SOLOMY LLC
▪️ Carrier 30XA0702 (2009) — 674 kW
▪️ Solution: Efficient cooling for composting and fruiting zones
YABLUNIVSKYI PRODUCTION COMPLEX
▪️ Trane CGAM 120 (2015) — 325 kW
▪️ Trane RTWB 210 (2004) — 322 kW
▪️ Solution: Cooling of production plant and storage chambers
DINBO LLC
▪️ EMERSON SLS 0540 (2011) — 482 kW
▪️ Solution: Stable year-round operation under variable loads
FUNGHI FARM LLC
▪️ Clivet WSAT — 404 kW
▪️ Solution: Reduced energy use and adaptation to new production cycles
MRAOVIC GBR — Austria
▪️ Clivet WSAN-YSI — 22.2 kW
▪️ Solution: Compact solution for a small-scale farm
Tomasz Wiera — Poland
▪️ Clivet WSAN-XIN MF — 18.2 kW
▪️ Solution: Precision temperature control for organic mushroom farming
EVROPROM — Your Trusted Partner for Mushroom Cooling Solutions
Our catalog includes over 200 chillers from 8 to 1300 kW, all tested and ready for shipment:
– Individually selected to match your production needs
– Engineering support for design and selection
– Delivery and commissioning across Europe
– Warranty up to 36 months
📩 Contact us: info@evroprom.com
🌐 Equipment catalog: www.evroprom.com
📞 +48 799 355 595 | +48 511 705 715
Author: Dmitry Lychak,
CEO of EVROPROM
27.06.2025