Mr.Hiroshi Ohmae; Nankai cool-warm installation CO. LTD. in Kochi

１．We want to keep that the tolerable temperature difference for each refrigerator shall be ±0.2℃(within 0.4℃).
And the usual setting temperature shall be -1.5℃.

A．
Most refrigerators are set at ±1℃ difference and most thermostats are set by 1℃ or 0.5℃ so….

① We have specially ordered thermostats that can be set by 0.1℃.

②　We have increased the number of our Unit Coolers and Condensing units (34 unit coolers, 11 condensing units) and distributed cooling force to minimize the unevenness of the temperature in the warehouse and the excessive cooling. We have also been able to prevent increasing temperature during defrosting (when one unit defrosting, other unit operate to maintain the desired temperature).

２．We want to avoid moisture evaporation (drying) of the stored contents by wind from unit coolers.

A．
We have increased the number of unit coolers to reduce wind speed and maintain steady and slow air circulation.

３．We want to avoid uneven temperatures inside the warehouse.

A．
In addition to the adoption of unit coolers with specially ordered thermostats, the smooth circulation of cold air was realized by attaching the round parts to the corner connection of ceiling and wall surfaces.）

４．
We want to keep humidity in the warehouse over 85%.

A．
Commonly, the range of humidification is limited in + temperature zone, and the humidification is rarely performed in – temperature zone (because water will be frozen).

Besides, humidity controller can not be used in – temperature zone.
We first planned to use a ultrasonic humidifier, but there were some problems concerning initial costs, installation work, breakdown etc. So, we decided to use a special nozzle (spray nozzle producing fine mist atomization with droplet diameter of 10 microns) and control the humidity by a timer.

５．Even when some units break down, the contents of the warehouse will not suffer damage.

A．
Our unit coolers are installed above pathways in the warehouse so that water will never fall onto our products. We use multiple unit coolers that operate independently so that even if some units break down, other working units will compensate for the non-working unit. This prevents the quality loss caused by increasing temperatures and obviates the need to move stored products. In addition, this cool-warm-warehouse has its own electric generators in preparation for blackouts from disasters.

In addition, this cool-warm-warehouse has its own electric generators in preparation for blackouts from disasters.

６．When the temperature is too low, contents will be frozen.
A．
The unit coolers in each room have a warming function, and we are able to set the maximum and minimum temperatures, which will automatically be regulated by the refrigeration unit.

Incidentally, the refrigeration units in this warehouse meet specification for the use in the range of setting temperature from 25℃ to -20℃, which may not be necessary for the purpose of use in Nakamura-Noen Co., Ltd.

Summary

　The contents of the refrigeration units are living organisms, and need to be preserved for a long time in the controlled freezing range (unfrozen temperature range below 0℃). There were many problems such as uneven temperature, temperature difference, required temperature range for use, humidity, residual gases given off by living organism, initial costs, running costs and so on.
Our company, which is specialized in refrigeration, is highly interested in these problems and pleased to have been given the opportunity to solve these problems.