There is a great market demand on needle mushroom in China, which is of high nutrition. The conditions of cultivation need be carefully controlled, to which the quality of mushroom can be really sensitive. Industrial cultivation of needle mushroom has become more and more popular in China with precise control of its growing conditions, ensuring the production level with satisfying quality. Glacier coolant has been utilized in many refrigeration systems for cultivation of needle mushroom.
The main production flow of needle mushroom is: Cultivation of raw material – Sterilization by steam – Cooling – Inoculation – Budding -Forcing – Germination – Adaption – Maturation – Package – Out of stock. It requires different humidity and ventilation level at individual stage. The refrigeration system must deliver the right temperature, humidity and amount of air. The detailed requirements are listed in Table-1:
At the moment, small capacity refrigeration systems for cultivation of needle mushroom deploy direct refrigeration system which consists of compressor, air condenser, air cooler and expansion control valve. There are some manufactures utilizing refrigerated storage system. Although direct air coolers have high heat capacity, the distance between fins is quite small (2~2.8mm). Frost forms on the surfaces of fins blocking the gaps between them, resulting in loss or even no heat transfer of cooling circuits. Due to the fire-proofing nature of insulation material, only natural deforest is allowed, which is time consuming. Mushroom’s quality is also reduced by variation of refrigerated storage system’s temperature. Utilization of Glacier Coolant as secondary refrigerant for large capacity refrigeration systems are strongly recommended. The refrigerated storage system is stable with temperature variation within 0.5℃. The refrigeration system consists of primary refrigeration system including screw compressor, evaporative condenser、secondary refrigerant pump、buffer station、indirect air cooler and weighted percentage motorized control valve.
Glacier Coolant Refrigeration system is selected for a project which produces 160 ton/day needle mushroom. Based on the operating temperature of each room, we proposed the solution of providing two coolant streams: -5℃ for product storage (0-4℃) and maturation room (4-6℃); 3℃ for cooling room, incubation room, inoculation room and package room. There are multiple primary refrigeration systems and corresponding evaporative condensers which can be standby system for one or another. No redundant fans are required. The whole site is segmented and each segment is installed with two variable speed pumps which adjust the coolant flow rate depending on demand. Heat recovered from the primary refrigeration system is used for defrost as well as heat input required for incubation room. The production site is located in Northern China and the load capacity can be adjusted by switching on/off systems based on ambient temperature during winter, minimizing the power consumption. The Glacier Coolant type is LM-4, featuring great heat capacity and low viscosity at operating temperature. The system is highly energy efficient and there is no flashing point for the coolant, eliminating risk of fire. The coolant is highly anti-corrosive, much lowering the deterioration rate of the equipment and saving maintenance cost during production life.
Refrigeration systems utilizing Glacier Coolant designed for cultivation of needle mushroom provide high level of automation and can be delivered in completed assembly. It is energy efficient, requires minimum level of maintenance and can be applied to large scale of industrial production.