Climate control in fruit and vegetable
Climate control in fruit and vegetable warehouses
Regulation of Humidity & climate control in fruit and vegetable warehouses
The measurement and monitoring of relative humidity make it possible to control and regulate humidification through installed fogging systems. They come into action when the humidity is too low. If the humidity is too high, ventilation or heating systems can help.
Losses of commercial crops due to improper storage and handling can range from 10 – 40%. Proper storage conditions – temperature and humidity – are needed to increase storage life and maintain quality once the crop has been cooled to the optimum storage temperature. Fresh fruits and vegetables need low temperatures => 0.5 – 12°C and high relative humidity => 90 – 98 % to lower respiration and to slow metabolic and transpiration rates. By slowing these processes, water loss is reduced and food value, quality and energy reserves are maintained.
Ideal conditions in fruit an vegetable warehouses leads to higher quality
Challenges for modern measuring technology in Fruit and Vegetable Storage Facilities
The most popular air humidity measurement principle used is the capacitive technology. This measuring principle essentially consists of a special polymer which can absorb and release moisture to match the room humidity and in the process experiences changes to its electrical capacitance.
This and similar measuring principles such as the psychrometric principle (with 2 temperature probes) react rather sluggishly to changes in the measured value or even remain at high humidity levels for a long time until the sensor releases the water stored in the polymer again and can determine the real measured value, which means that changes in high humidity levels during the monitoring process are detected very slowly or not at all.
The consequences are high hysteresis, inaccuracy, limited sensor lifetime and sudden sensor failures. This can dramatically increase cost of operation (excessive use of water), maintenance (frequent recalibration) and service/repair (sensor replacement).
The more reliable the humidity and moisture measurement for your storage procedure is, the more accurate the climatic environment can be regulated. Since temperature and relative humidity are among the factors that prolong storage life and nutritional quality. Reliable measurements save energy and enable constant quality control of the product.
The sensor should react quickly and linearly to changes in climate, even at humidity levels of well over 90% RH and be unaffected by low temperatures around the freezing point. A high level of accuracy with a measurement uncertainty of less than 1.5% is required to enable a grower to maintain optimum conditions for maximum storage life of the crop. It will also help to minimize crop damage from chilling, freezing, heating and water loss from the crop. Close attention to storage conditions will yield returns through greater customer satisfaction, less waste and spoilage and the flexibility to hold a crop without significant storage losses to wait for better prices.
Regular checking and maintenance of the sensors is therefore essential. For this reason, Novasina also offers various options for checking the installed sensors yourself regularly and without great effort or by specialized personnel.
The most important factors to consider when choosing an RH/Temp sensor for crop storage facilities are the response time, possible external influences, accuracy and maintenance intensity. Novasina’s RH/Temp sensors meet all these requirements while still being affordable. Find out more about our climate measurement devices below.