BUD Holland switches to natural refrigerants

"We are extending our possibilities with the new ripening chambers," says Cor Burghoorn, financial manager at BUD Holland. "Besides ripening exotic fruit the ripening chambers are also a solution for products that need airing or for which the air humidity has to be reduced." The multifunctional ripening chambers are all individually adjustable within a wide temperature range. This means they are suitable for ripening various kinds of fruit, such as mangos, avocados, papayas and of course bananas. A ethylene-gassing system is installed for controlled ripening.

Nijssen developed special coolers for ripening chambers to be able to condition products equally. By foreseeing the ventilators of a frequency control, very precise air division can also be realised when the ripening chamber is partially full. An electrically controllable stair cover (trapafdekking) ensures that the conditioned air is sucked through the stacks of produce. The product temperature as well as the air temperature is measured constantly. To maintain an accurate relative humidity, the ripening chambers are all foreseen of a humidifying system and a dehumidifier. Each chamber is also foreseen of its own ventilation system for controlled supply of outside air. 

The advanced Ripeningmaster® control programme, that was developed by Nijssen, ensures full automatic control of the cooling, heating, humidity control and gas. Per ripening chamber and per product a conditioning programme can be pre-programmed for a period of one day through to a number of weeks. The control ensures that temperature changes between the storage period and the ripening period are realised evenly, with a course that provides the best result for the product. In this way the specialist product knowledge of the riper and the optimal control of the installation make for perfect quality at the end of the storing and ripening process. The final result is a gorgeous 'ready to eat' fruit.

Application of the present refrigerant Freon (R22) has been prohibited for new buildings and extensions since 2010. That's why BUD Holland decided to replace the existing installation during the extension. "This installation was realised by Nijssen in 1994," says Cor Burghoorn. "In all those years we've never have any long term drop out, partially because we know Nijssen to be a very reliable partner in maintenance. They're always on time with the checks. They always let us know when sometime might go wrong and take appropriate measures on time. Therefore, Nijssen was the preferred supplier, but we did ask two other reputable builders to submit offers. After viewing the know-how and, of course, the price, we, in agreement with our advisor, once again chose Nijssen."

Four Bitzer screw compressors ensure a total cooling capacity of 722 kW at an evaporation temperature of -8°C. By foreseeing the compressors of an economiser a high COP value of 4.07 is reached. At the ammonia circuit, two cascade coolers are connected. One cooler, with a capacity of 560 kW supplies the cooling for the cooling cells through the secondary CO2 circuit. In the second cooler a water/glycol mixture is cooled to a temperature of around -6°C. For the freezing installation a total COP of 2.00 is realised with the CO2 cascade system. This is an increase in efficiency of 25% compared to the old Freon installation.

Due to a phased execution, a tight plan and intensive talks with the client a company break was prevented. First the new machine room and six ripening chambers were built. After the central ammonia/CO2 installation was put to use the cooling cells were remodelled two by two and connected to the new installation. "The six new ripening chambers can also be used as cooling cells," Cor Burghoorn adds. "Our warehouse boss has been able to lead everything well." Finally, the freezing cell was connected to the central installation and the present Freon installation removed.

Due to the very high thermodynamic efficiency of CO2 as well as ammonia an installation was built with a low energy use. One of the energy saving components in the installation is the heat recovery system. The free heat from the cooling installation is used for heating the ripening chambers, among other things. All the heat needed for this can be recovered from the installation. The generated heat is also used for defrosting the coolers. By using natural refrigerants and various energy efficient components the installation qualifies for an EIA contribution.