Brazed Plate Heat Exchangers

Brazed Plate Heat Exchanger in Ammonia Systems

Ammonia refrigeration systems are, as the name implies, a system of refrigeration that uses ammonia. The ammonia is the chemical that is used to absorb the heat from one area, and bring it to another area to dissipate. Enhanced heat transfer equipment has been widely used by the hlocarbon-based air conditioning industry. The persistent issue of ozone and global warming has led to interest in natural refrigerants, such as ammonia, which has played a prominent role in the refrigeration industry for years, particularly in the fields of food, beverage, and marine.

Traditionally, chillers, condensers, oil coolers, and other heat transfer equipment for ammonia refrigeration systems have been constructed with plain surface tubes. This trend has been prevalent for two reasons. First, ammonia is not compatible with copper alloys,whereas most highly efficient heat transfer surfaces have been developed in copper and copper alloys.

Brazed Plate Heat Exchanger in Oil Coolers

Brazed Plate Heat Exchanger in Evaporators

Brazed Plate Heat Exchangers in the evaporator process of refrigerators change the liquid into the gaseous state and removes the heat through the cooling fluid. Heat transfer in evaporators is governed by the equations for heat transfer to boiling liquids and by the convection and conduction equations. The heat must be provided from a source at a suitable temperature and this is condensing steam in most cases. The steam comes either directly from a boiler or from a previous stage of evaporation in another evaporator.

Frequently in the food industry a raw material or a potential foodstuff contains more water than is required in the final product. When the foodstuff is a liquid, the easiest method of removing the water, in general, is to apply heat to evaporate it. Evaporation is thus a process that is often used by the food technologist. The basic factors that affect the rate of evaporation are the: rate at which heat can be transferred to the liquid, quantity of heat required to evaporate each kg of water, maximum allowable temperature of the liquid, pressure at which the evaporation takes place, changes that may occur in the foodstuff during the course of the evaporation process.

Brazed Plate Heat Exchangers as Heat Pumps

Heat pumps are electrically driven systems used to heat residential or commercial areas. In reversible operation, they are also used for cooling. Heat is produced during a condensation process in the refrigeration cycle and is transferred to either air or water. (The opposite applies to cooling.) The heat exchanger in contact with the energy source is the evaporator. The heat exchanger producing the hot water is the condenser. As with all heating and cooling systems, the aim is efficiency. In a heat pump, this is achieved by ensuring the closest possible temperature between the evaporator and the condenser. Optimizing the heat exchangers is therefore critical.

The heat generated by a heat pump is used for space heating but also for producing hot tap water. To enhance the production of hot water and increase efficiency of the heat pump, an economizer is often used. It helps the compressor to achieve higher condensing temperatures, thereby raising the water temperature. In applications where very high temperatures are required, heat pumps can be designed as cascade systems or use CO2 as refrigerant. Brazed heat exchangers (BHE) are commonly used in heat pumps. They act as condensers, as evaporators in water-to-water and water-to-brine systems and, optionally, as economizers. Vitherm Brazed Plate Heat Exchangers are a popular option for any systems requiring heat pumps.

Brazed Plate Heat Exchanger in CO2 Supermarket Refrigeration Systems

The Brazed Plate Refrigeration Heat Exchanger  is the most efficient and compact heat exchanger for refrigeration applications. They can be supplied in single and dual circuits designs for evaporator and condenser applications. The Brazed Plate Refrigeration Heat Exchanger is a variant of the traditional Gasketed Plate Heat Exchanger. It is composed to a number of ‘herringbone’ corrugated Type 316 stainless steel plates brazed together in a vacuum furnace to create a bond that allows it to operate at pressures over 600 psig. Advantages of BRAZED PLATE over other technologies The brazed plate heat exchanger for refrigeration applications is the most efficient heat exchanger in the refrigeration industry. 

The induced turbulence through the channels formed by the herring bone corrugations allow for the liquid to flow in a forced turbulence pattern providing up to 3-5 times higher heat transfer coefficients compared with tubular heat exchangers. The refrigeration brazed plate heat exchanger weighs about 30% less than coaxial for a similar capacity and occupies 25% space compared to other technologies. There is a tremendous advantage over other heat exchangers for installation on skids and in restricted spaces where space is a premium. The low hold up volume in a brazed plate heat exchanger on the refrigerant side is about 10 times lower than a tubular heat exchanger. The major advantage to this that the there is a rapid response to capacity changes and a low filling volume reducing refrigerant costs.  A copper brazed PHE can also be used as a condenser.