A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids. Types of compressors The main and important types of gas compressors are illustrated and discussed below:   Positive displacement Positive displacement compressor means a system which compresses the air by the displacement of a mechanical linkage reducing the volume (since the reduction in volume due to a piston in thermodynamics is considered as the positive displacement of the piston).   Reciprocating compressors Reciprocating compressors use pistons driven b […]

Thermostatic expansion valves (TXVs) are one of the most common types of adjustable orifice throttling device in air conditioning and refrigeration systems worldwide. They earned this place by being both efficient and affordable. But how do TXVs compare to other throttling devices? Fixed orifice devices like capillary tubes or pistons are cheaper and electronic expansion valves (EEVs) offer greater superheat control across a large load range, so why are TXVs so popular? Fixed Versus fixed orifices: orifice devices are ideal throttling devices if conditions never change. If the load on the system is constant and the ambient temperature remains steady, then a simple capillary tube or piston would be preferable to an adjustable orifice device like a TXV. However, outside of a laboratory, static conditions are simply not realistic. Seasonal temperature changes have a profound effect on system performance, as does increaseing the heat load i […]

For the commercial food service and related industries – which rely daily on large quantities of ice for food displays, safety, preparation, beverages and more – the ability to reliably and cost-effectively produce ice can have an impact on a business’ operation. Between 2005 and 2010, Manitowoc Ice, Inc., the Wisconsin-based manufacturer of commercial ice machines, became interested in taking their product portfolio one step further and turned to Danfoss with the idea to design an ice machine that would improve customers’ sustainability efforts by operating on natural refrigerants. The collaboration with Danfoss led to the development of two new models within Manitowoc’s Indigo Series and two Q-Series under-counter units that are cooled by R290, or propane, which Manitowoc introduced in mid-2011. The use of an environmentally friendly hydrocarbon refrigerant enables Manitowoc to offer customers a product that has zero ozone depletion p […]

The Dog is the eleventh of all zodiac animals. According to one myth, the Jade Emperor said the order would be decided by the order in which they arrived to his party. Monkey, Rooster and Dog were in another country, helping a god defeat evil spirits. After, they set off to the party together. Because they arrived at the same time, the Jade Emperor went by the order they met the god in the other country. Thus, Dog became eleventh. The Dog is also associated with the Earthly Branch (地支—dì zhī) xū (戌), and the hours 7–9 in the evening. In the terms of yin and yang (阴阳—yīn yáng), the Dog is yang. In China, it is still popular to name dogs Wàng Cái (旺财). It means “prosperous wealth” and comes from dogs’ barking sounds (旺旺—wàng wàng). Honest and loyal, Dogs are the truest friends and most reliable partner. Recent years of the Dog are: 1934, 1946, 1958, 1970, 1982, 1994, 2006, 2018 Bàinián and kowtow It can be said that Chinese culture is bas […]

Cold storage, also known as controlled atmosphere storage is the most advanced method of storage of fresh fruits and vegetables. It is based on refrigerated, increasing gas component adjusted by the storage environment, temperature, humidity, carbon dioxide, oxygen concentration and ethylene concentration and other conditions of control, inhibition of respiration of fruits and vegetables, slow down the metabolic processes, better to keep fruits and vegetables fresh degree and commodity, and to extend the shelf life of fruit and vegetable storage (sales shelf life). Typically atmosphere storage than conventional refrigerated storage period may be extended 0.5-1 times; fruits and vegetables controlled atmosphere storage library after library start with “sleep” state “wake up”, which made of fresh fruits and vegetables after the library (Sales shelf life)  may be extended 21 to 28 days, 3 to 4 times the normal refri […]

The field of refrigerant regulation is constantly changing, with additional regulations being announced on a nearly annual basis. Whether as a way to fight against ozone depleting substances or in an attempt to slow climate change, global refrigeration treaties like the Montreal and Kyoto Protocols have been phasing out refrigerants since the 1980s. One refrigerant that is not at risk to be phased out is carbon dioxide or CO2. CO2 is has the lowest possible GWP rating of 1 and poses no risk to the ozone layer, making it immune to future regulations. And while CO2 is a very efficient refrigerant, it has limitations, particularly with regard to high ambient temperatures. However, emerging technology may have finally overcome this shortcoming. This article is intended to serve as a review the different technologies related to CO2. To better establish the differences between each kind of system, we will review each one, starting with booste […]

A blast freezer is a device quickly lowering the temperature of the introduced foodstuff, either fresh or pre-cooked, maintaining its peculiarities during storage. Blast Freezers work by rapidly freezing contents at a level in which stops bacteria from deteriorating the product, allowing it to be persevered for a longer period of time. The blast freezer operates in full compliance with the HACCP standards, which originated from the need for maintaining the food’s healthiness. The HACCP system is designed to assess all possible risks that may affect the food’s healthiness at each stage of its production: it implements preventive measures, instead of focusing just on the inspection activities carried out on the finished product. In other words, this control is designed to monitor the whole food production and distribution process. There are many different kinds of chilling, depending on the characteristics of the food and on h […]

Modern industrial production, storage, and distribution would be impossible without the extensive use of refrigeration. Ammonia (NH3) has long been the prevalent refrigerant in industrial refrigeration due to its high degree of efficiency, low environmental impact, and affordability. Ammonia is commonly used in food processing facilities, dairies, breweries, meat processing plants and cold storage warehouses, where a large cooling demand is required. Ammonia is a cost-effective and efficient refrigerant. The only drawback is its classification as a poisonous refrigerant that in case of leakage can be harmful to personnel and the food items that the refrigeration system was designed to protect. The risk of leaks arises from many different sources, ranging from inadequate operating procedures or lack of training to failures in piping, welds or poor maintenance. Due to its classification as a poisonous gas, design, construction and operati […]

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