Heating and Cooling systems

The heating and cooling system is the heart of the house. When buying a house, at least you need to know:

- what kind of heating and cooling system is in place?

- what condition it is now?

- how much does it cost to operate?

Heating system types:

The most common heating systems include:

1) Forced Warm Air (FWA)

This is the most common type of the heating system. A furnace heats air, and a blower sends the hot air through the house. Return vents and pipes bring the cool air back to the furnace to be heated. Furnaces have a capacity rated in BTU's, which are simply British Thermal Units. The number of BTU's given represents the furnace's heat output from either gas, oil or electric firing.

2) Steam heating system

This kind of system usually found in older homes. A furnace heats water until steam forms. The steam circulates through pipes into radiators in the rooms. As steam cools, it turns back into water, which then returns to the furnace.

3) Hot water heating

This system works like a steam heat, but instead of circulating steam, it circulates hot water that heats the rooms.

4) Baseboard / electric heating

This system uses heating elements placed along the baseboards of walls.

5) Radiant heating system

This type of system uses pipes built into the floor and/or walls to heat the rooms.

Energy Guide labels

Heating and cooling systems are some of the most important investments that can be made for the home. Buying a new house? Renovating an old one? Making an emergency purchase because the old one finally conked out? A lot depends on the choices you make. Comfort and safety are at stake, and so your money.


According to the Department of Energy (DOE), typically about 45 % of utility bills goes toward “space conditioning,” or heating and cooling a home. While the price of equipment and cost of repairs and maintenance are important to consider, do not forget about system operating costs. Hefty space conditioning costs may be lowered by choosing the most energy-efficient equipment that meets your needs and fits your budget.

The Federal Trade Commission, the nation’s consumer protection agency, wants you to know that it enforces the Appliance Labeling Rule, which requires EnergyGuide labels on certain appliances, including:
• room and central air conditioners,
• furnaces, boilers and heat pumps.
The labels let you know how energy efficient a model is compared to others like it.

Koi Pond Heaters

There are many reasons for heating your koi pond, maybe you just want to see your enjoy your pond in all seasons. Whatever your reason we just want to give you some insight to make it easy to accomplish. There is now new technology, energy efficient heaters being developed for pond heating. Therefore we recommend electric koi pond heaters, submersible heaters, heat exchangers and floating pond heaters.

Pond heating Considerations:

First you must determine whether you want to de-ice or actually heat your pond to a specific temperature. Deicers melt the ice to provide an opening for harmful gas exchange only. Heating your pond to obtain a specific temperature can be a bit technical, so if your not sure about the heater sizing we recommend that you contact our koi pond heating specialists. The outside low temperature is the key to your kilowatt requirements and unfortunately it can vary. Your heater output kilowatts are calculated based on your low ambient temperature and if your geographical area drops far below that normal low temperature a safety factor should be included in the calculations. We recommend submersible pond heaters for small to medium size ponds and energy efficient heat exchangers for large ponds

Koi Pond Information:

One period when koi keepers traditionally have their most difficult time with health problems is during the transition from winter to spring. As waters begin to warm up, pathogens are able to multiply at a more rapid rate than koi can defend themselves leading to an increase in the likelihood of disease. If a pond is heated over winter, then this risky period is removed from the koi owners. View info Pond Heaters

The major reasons for pond heater failures:

Pond water is usually high in calcium chloride and other minerals,this causes build up on heaters. In time the build up prevents heat transfer and the heater internally burns out. Our new technology completely eliminates any build up.

Salt additives to pond water eventually corrodes the heater surface. We have developed heaters that can’t be attacked chemically. The most popular cause of pond heater failure is low liquid burnout. Our new pond heaters don't burn from lack of liquid, they can run in air and will shut themselves down before burnout. Visit our web site Heating Your Pond.

By Kirk Rogers

Koi Pond Heating

There are many reasons for heating your koi pond,maybe you just want to see your enjoy your pond in all seasons.Whatever your reason we just want to give you some insight to make it easy to accomplish. There is now new technology,enery efficient heaters being developed for pond heating.Therefore we recommend electric koi pond heaters,submersible heaters,heat exchangers and floating pond heaters.Pond heating Considerations: First you must determine whether you want to de-ice or actually heat your pond to a specific temperature .Deicers melt the ice to provide an opening for harmful gas exchange only. Heating your pond to obtain a specific temperature can be a bit technical, so if your not sure about the heater sizing we recommend that you contact our koi pond heating specialists. The outside low temperature is the key to your kilowatt requirements and unfortunately it can vary. Your heater output kilowatts are calculated based on your low ambient temperature and if your geographical area drops far below that normal low temperature a safety factor should be included in the calculations.We recommend submersible pond heaters for small to medium size ponds and energy efficient heat exchangers for large ponds.

* Pond Heating: There are conditions that effect pond heaters and make it more difficult controlling pond temperature.

* Pond Waterfalls are used for aeration and beauty,but they cool the water and work against the heating process.

* Pond Water Depth a good designed koi pond should be at least three foot in depth,shallow large exposed surface area ponds are easily effected by wind chill factors and require larger pond heaters to maintain temperature.

Koi Pond Information: One period when koi keepers traditionally have their most difficult time with health problems is during the transition from winter to spring. As waters begin to warm up, pathogens are able to multiply at a more rapid rate than koi can defend themselves leading to an increase in the likelihood of disease. If a pond is heated over winter, then this risky period is removed from the koi owners.

Do not raise the koi's water temperature too fast. Parasites and bacteria can also grow more quickly in warm water. The fishes system takes time to adjust but the disease organisms do not. Raise the temperature from ambient at 3 - 5 degree intervals every 24 hours to 80 - 84 degrees Fahrenheit. Maintain a stable temperature with less than 2 degrees variable per day Treat with 0.3% salt and parasiticides or antibiotics during the adjustment period, and continue with medication if necessary until cure is affected. Maintain temp. for 4 - 6 weeks after cure, then slowly drop the temperature to match that of the pond water. This will ensure a stronger Koi and ease the fishes transition back to the pond.

By Kirk Rogers

The Importance of Keeping your Heat Exchanger Clean

Heat exchanger air water cleaning is an absolute necessity in order to keep your production system running smoothly. If your heat exchanger is not kept as clean as it should be, it will not be able to function properly and the heat exchange process will not take place efficiently. This will lead to significant problems down the line if it is not dealt with as soon as possible. However, simple cleaning alone will not suffice to keep everything in tiptop shape.

An air-to-water heat exchanger is highly specialized equipment intended to be used when ambient or air temperatures are higher than 130 degrees Fahrenheit. Industrial air conditioners are unable to cool machinery when the ambient temperature is at that level, because the refrigerant their compressors produce is at around 150 degrees Fahrenheit, and there is too little difference between the two temperatures for the refrigerant to do its job. In cases such as these, air-to-water heat exchangers come into play. They bring the enclosure interior below the temperature of the ambient air so that the equipment can function properly.

At its most basic, heat exchanger air water cleaning is simply making certain that both the air and the water utilized to dissipate the heat from your process system are kept clean. If for instance the mechanism of your system that brings in the air is a cooling tower, you will have to realize that when it brings the air into your system, all the debris that happens to be in the air will enter the system along with it. This debris can then enter the system, build up within it, and restrict proper operation – and eventually cause a malfunction, perhaps even a serious one. So simply keeping your heat exchanger system clean would appear to be the solution to this problem.

However, critics have compared this to taking a cold tablet when one has a cold, and with good reason. While cleaning the heat-exchange system will ensure that it is free of anything that could cause problems, it does nothing whatsoever to prevent the problem from recurring, especially in areas where there is plenty of debris that could potentially cause some sort of jam. In that sense, simple cleaning will not be enough.

The ultimate solution, then, would be to install excellent filtration technology to keep the debris from entering the system in the first place, and combine this with diligent cleaning.

So ensure that you install the proper filters and filtration technology and religiously perform your heat exchanger air water cleaning operations to enable your entire system to function optimally.

By Sabrina Rocca

Cleaning Your Heat Exchanger Tubes

Cleaning your heat exchanger tubes is a job anyone can do if they know how. If you are a do it yourselfer then you should have no trouble with this task.

There are several methods to clean exchanger tubes. Here are a few of them; one is to use chemicals for the cleaning. Another is to use high-pressure water system. One last method is to employ mechanical cleaning using brushes, scrapers and abrasive balls. These are the best ways to clean the tubes.

Regular cleaning of the exchanger tubes should prolong the life of the entire unit. It will help it work at its maximum efficiency as well.

Many people use a heat exchanger system to heat their swimming pools these days. Having the ability to clean your own exchanger tubes would be a good way to save money and keep your system in top working order.

It would be beneficial to clean the exchanger tubes every few months. At least inspect them to see if they need to be cleaned. If they do not need to be cleaned, and then make sure that, they are thoroughly cleaned twice a year.

In order to clean the exchanger tubes properly, they must be removed from the system. Remove any loose material that is near the ends of the tubes and inside them as well. Use a brush and push it down the tube to get the cleaning started. The brush should have good strong nylon bristles. This helps to loosen and remove any loose materials inside.

During this brushing process, you may find that there is some material stuck to the sidewall of the exchanger tube. A plastic or metal scraper will help to remove anything that is stuck to the wall. Be careful not to damage the tube. Do not use a scraper that is harder than the material of the wall of the tube.

Try not to scratch the wall of the exchanger tubes as it could cause the tube to not function as well as it should because particles could stick to the scratches in the tube. Therefore, a plastic scraper would be best.

As a last step in cleaning the exchanger tubes, you could use a water jet to force out any loose particles that were missed with the previous methods. If you have any calcium deposits on the tubes then you will need chemicals to remove them.

Now you have the basics for cleaning your exchanger tubes. Gather as much information as possible before tackling this do it yourself job.

By M. Applebaum
(ArticlesBase SC #720822)

The use of plate heat exchange equipment for winemaking

In the winemaking process heat exchange equipment is used at all stages of the process, such as for processing grapes, mash, to accelerate the maturation of wines. It used for specialized types of wines, as well as filling and in the production of sparkling wine - in preparing the fermentation mixture, the secondary fermentation, bottling of the finished champagne, the stabilization of brandies, to accelerate maturation of brandy spirits.

This is because the heating and cooling, as purely physical methods of impact on the wine, not associated with the introduction into it of other, not peculiar substances. On the other hand, these techniques cause the complex physics-chemical and biochemical processes, many of which are similar to the processes taking place during maturation and aging of wine in the wild. For all these technological stages, heat transfer equipment of various types is used, and, in the first place - frame plate heat exchangers.

Heat transfer surface of the plate heat exchanger consists of a set of plates with seals, pairs of lines for the passage of fluids. Pack plates secured between the stationary and the pressure plate and hermetically tightened bolts.


Figure 1: Construction of one-section plate heat exchanger

The plates are assembled into the package through many contact points, thus ensuring resistance of the design to high pressure. Corrugation pattern of the plates enhances turbulence, and reduces the probability of sediments on the plate surface. The minimum temperature difference between heating medium inlet and outlet can be 1 ° C, which is particularly valuable for the section of regeneration in the pasteurization equipment.

Package can consist of plates with different corrugation patterns.
Plates with horizontally oriented profile characterized by high heat transfer rates with relatively large pressure differences, whereas for a plate with a vertically oriented profiles are characterized by small variations in pressure with less heat transfer rates.

Combining the horizontal and vertical profiles can obtain the optimal values of hydraulic resistance and heat transfer coefficients.
Large variety of types of plates makes effective use of plate heat exchangers for different processes.

How Heat Transfer Works

Heat transfer occurs when there is a difference in temperature between two mediums. Heat will travel from the hot source to the cold source. The rate at which the heat transfer occurs at is determined by many factors such as the heat conductivity of the two materials andthe difference in temperatures of the two mediums. Convectiuve heat transfer occurs when the materials are moving against each other.

Plate heat exchangers have significantly good heat transfer rates because they use metal plates which have high heat conductivity rates and the plates are extremely thin. The plate heat exchangers also achieve high amounts of heat transfer through convective forces with both working fluids. With large temperature differentials, great amounts of heat transfer can be achieved using a plate heat exchanger.

Compact heat exchangers

Brazed plate heat exchangers designed for use in a variety of liquid-to-liquid heat transfer applications, where reliable, efficient and compact heat exchangers are needed. Compact brazed plate heat exchangers can be flexibly used in most types of heating systems, including radiant floor heating, radiator system, tap water system, and other sanitary water applications.

Applications and advantages of brazed heat exchangers

Brazed plate heat exchangers are designed for highly efficient transfer of energy between liquid, vapor and gaseous environments.

Brazed plate heat exchangers have the following advantages:
- High reliability due to design features and advanced technology manufacturing;
- High efficiency plate heat exchanger;
- Wide range of operating temperatures;
- High working pressure;
- High corrosion resistance of plate heat exchanger;
- Compactness and light weight plate heat exchanger;
- Small internal volume;
- Wide range of capacities and dimensions;
- Ease of installation and maintenance of plate heat exchanger;
- Low cost of plate heat exchanger.

Applications of brazed plate heat exchangers:
- Heating and hot water (steam and water heaters);
- Ventilation systems;
- Air conditioning in rooms and buildings;
- Refrigeration: Evaporators, Condensers;
- Consisting of heat pumps: evaporators, condensers, intermediate heaters and coolers;
- For different technological needs (coolers, heaters);
- Water heaters in pools, etc.

The design of brazed plate heat exchangers

Brazed Heat Exchangers consist of high quality steel plates that are vacuum brazed into one compact, pressure resistant block. For the solder are widely used copper or nickel. In assembling each second plate is rotated 180 degrees, forming a channel separation for the heat transfer medium.

For special applications (depending on type) may create a parallel stream media. Some profile plates or extra built-in turbulence plate provides a high degree of turbulence, which ensures efficient heat transfer even at low volume and reduces costs to a minimum the risk of contamination.

Heat exchangers for chiller applications

Understanding the thermodynamic and transport properties of fluids - combined with simple calculations to define a specific heat transfer problem - will help you select the appropriate heat exchanger for your liquid chiller application.


Numerous types of heat exchangers are used in chiller applications. They serve the specific purpose of controlling a system’s temperature by removing thermal energy. Although there are numerous sizes, levels of complexity and types of heat exchangers, they all use a thermally conducting element, typically in the form of a tube or plate, to separate two fluids so that one can transfer energy to the other.
When selecting the proper type of heat exchanger, one faces the fundamental challenge of fully defining the problem to be solved, which requires an understanding of thermodynamic and transport properties of fluids. This knowledge can be combined with simple calculations to define a specific heat transfer problem and to select the appropriate heat exchanger to use.

Fluid Flow Properties

Fluid flow inside the heat exchanger is a major consideration when selecting what type of exchanger is the best choice in a specific application. Fluid flow will be either turbulent or laminar. Laminar flow heat transfer relies entirely on the thermal conductivity of fluid to transfer heat to the heat exchanger surface. Laminar flows have lower film coefficients than turbulent flows.
Turbulent flows rely not only on thermal conduction but also thermal convection due to the increased fluid movement created in this type flow, thus producing better heat transfer. The higher film coefficients create less resistance to heat transfer.

The heat exchanger’s fluid flow can be determined from its Reynolds number. If the Reynolds number is less than 2,300, the fluid flow will be laminar. Fully turbulent fluid flow has a Reynolds number greater than 10,000. The transition region between laminar and turbulent flow produces higher thermal performance as the Reynolds number increases.

The type of flow determines how much pressure a fluid loses as it moves through the heat exchanger. This factor is important because higher pressure drops require greater pumping requirements. Laminar flow produces less pressure drop and increases linearly with the flow velocity.

This heat exchanger consists of a vertical set of plates welded together to form a cavity through which the colder fluid flows while the hotter fluid flows over the outside of the plates. The hot fluid cools as the fluid film flows down the plates. Most falling-film plates are embossed with intermittent welds placed throughout the plate surface. They can be single (top right) or double (bottom right) embossed.
Many types of heat exchangers are utilized in chiller applications. These range from shell and tube, brazed plate, semi-welded plate, welded plate and vertical falling-film plate. Each has specific characteristics that should be considered during the engineering selection process of a chiller system.
Shell-and-tube heat exchangers are used in applications where high temperatures and pressure demands are of great consequence. This type of design consists of a bundle of parallel tubes typically in a U-tube configuration. The bundle is supported by a series of baffles, which also helps to direct the flow across the tubes. Tubesheets close the ends and separate the two fluids.

The process fluid typically flows through the tubes to take advantage of the higher pressure capabilities inside the tubes and ease cleaning. The thermal performance of the shell-and-tube design generally is less than a plate design but the pressure rating is generally higher.

Brazed plate heat exchangers, like other plate heat exchangers, provide higher turbulent flow and heat transfer coefficients in a much smaller footprint. The plate material is typically AISI 316 type stainless steel. The herringbone plates are vacuum brazed to form the heat exchanger.

Brazed plate heat exchangers provide a highly efficient compact unit that will conserve space and reduce fluid volume requirements. Dual-circuit and double-wall models allow for numerous design options. The major factor to take into consideration is the fouling factor of the smaller channels. Because these units cannot be dismantled, filtration should be used on these heat exchangers.

Another variation of plate heat exchangers is the semi-welded plate heat exchanger. This type of heat exchanger utilizes the chevron-plate design to increase turbulent flow within the plate channels. The semi-welded heat exchanger consists of two plates laser-welded together into what is called a cassette. Plate gaskets seal between each cassette, and the cassettes are bolted together between end frames to retain the complete cassette pack. One fluid flows in the welded channel while the other flows through the gasketed channel.

Semi-welded plate heat exchangers have the same inherent advantages as all plate designs: higher turbulent flows, greater heat transfer coefficients and reduced fluid volume requirements. The largest difference with this design is the opportunity for expansion and ease of opening the unit for repair or cleaning. Cassettes can be added to increase the capacity of the heat exchanger.

The vertical falling-film plate heat exchanger design takes advantage of a large surface area for heat and mass transfer at the boundary of the two fluid flows. This design utilizes a vertical set of plates welded together to form a cavity through which the colder fluid flows. The hotter fluid flows over the external sides of the plates and is cooled when the film of fluid flows down the plate length. Typically, the plates are made of stainless steel for compatibility with sanitary fluids. An upper pan controls the external fluid flow with holes located over the plates.

This type heat exchanger allows closer approach temperatures between the fluids. The internal design of the plate cavity is critical. Most of these type of plates have an embossed design with intermittent welds throughout the plate surface. This helps to increase the turbulent flow inside the plates for higher heat transfer coefficients.

By considering the characteristics of the different types of heat exchangers at the beginning of a chiller selection, a more efficient system can be achieved.

Biological Fouling

The attachment of microorganisms (bacteria, algae, and fungi) and macroorganisms (barnacles, sponges, fishes, seaweed, etc.) on heat-transfer surfaces where the cooling water is used in as drawn condition from river, lake, sea and coastal water, etc., is commonly referred to as biological fouling. On contact with heat-transfer surfaces, these organisms can attach and breed, sometimes completely clogging the fluid passages, as well as entrapping silt or other suspended solids and giving rise to deposit corrosion. Concentration of microorganisms in cooling-water systems may be relatively low before problems of biofouling are initiated. Corrosion due to biological attachment to heat transfer surfaces is known as microbiologically influenced corrosion.


The techniques that can be effective in controlling biological fouling include the following:
1. Select materials that posses good biocidal properties.
2. Mechanical cleaning techniques like upstream filtration, air bumping, back flushing, passing brushes, sponge rubber balls, grit coated rubber balls, and scrapers.
3. Chemical cleaning techniques that employ biocides such as chlorine, chlorine dioxide, bromine, ozone, surfactants, pH changes, and/or salt additions.
4. Thermal shock treatment by application of heat, or deslugging with steam or hot water.
5. Ultraviolet radiation.

Fouling Resistance - Impurities

Fluids are rarely pure. Intrusion of minute amounts of impurities can initiate or substantially increase fouling. They can either deposit as a fouling layer or acts as catalysts to the fouling processes.
In crystallization fouling, the presence of small particles of impurities may initiate the deposition process by seeding. Sometimes impurities such as sand or other suspended particles in cooling water may have a scouring action, which will reduce or remove deposits.


Read the full article about fouling resistance.

Fouling Resistance -Velocity and Hydrodynamic Effects

Some of the parameters that known to influence fouling resistance are:

Velocity and Hydrodynamic Effects
Hydrodynamic effects, such as flow velocity and shear stress at the surface, influence fouling. Within the pressure drop considerations, the higher the velocity, higher will be the thermal performance of the exchanger and less will be the fouling. Uniform and constant flow of process fluids past the heat exchanger favors less fouling. Foulants suspended in the process fluids will deposit in low-velocity regions. Higher shear stress promotes dislodging of deposits from surfaces. Maintain relatively uniform velocities across the heat exchanger to reduce the incidence of sedimentation and accumulation of deposits.

Read the full article about fouling resistance.

Parameters that influence fouling resistances

Many operational and design variables have been identified as having well-defined effect on fouling. One of those parameters is Fluid Temperature.

A good practical rule to follow is to expect more fouling as the temperature rises. This is due to a “baking on” effect, scaling tendencies, increased corrosion rate, faster reactions, crystal formation and polymerization, and loss in activity by some antifoulants.

Lower temperatures produce slower fouling buildup, and usually deposits that are easily removable. However, for some process fluids, low surface temperature promotes crystallization and solidification fouling. For those applications, it is better to use an optimum surface temperature to overcome these problems.

Biological fouling is a strong function of temperature. At higher temperatures, chemical and enzyme reactions proceed at a higher rate with a consequent increase in cell growth rate.

Heat Exchanger Fouling

Fouling is defined as the formation of undesired deposits on heat transfer surfaces, which increase the resistance to fluid flow, resulting in higher pressure drop and reduced heat transfer. The growth of deposits causes the thermohydraulic performance of heat exchanger to degrade over time. Fouling affects the energy consumption and therefore increases the amount of extra material or fuel required to generate the required amount of heat transfer.

Principles of Heat Transfer

To understand how heat losses occur and how they can be minimized needed to understand the principles of heat transfer. Heat transfer finds application in equipment sizing as well. For instance, a heat exchanger is used to transfer heat load from one fluid to another. Thus, heat transfer applications are involved with energy transfer in equipment, piping systems, and building design.

Heat transfer is determined by the effects of conduction, radiation and convection.

Conduction - heat transfer is based on one space surrendering heat while another one gains it by the ability of the dividing surface to conduct heat. Metals are the best conductors of heat, while wood, asbestos, and felt are the poorer ones.

Radiation - heat transfer is based on the properties of light, where no surface or fluid needed to carry heat from one object to another

Convection - heat transfer is based on the exchange of heat between a fluid, gas, or liquid as it transverses a conducting surface.

Wort Cooling Systems

Wort cooling systems are employed to bring the wort to a temperature suitable for fermentation. Closed systems with plate heat exchangers have been used for several decades to prevent the danger of infection and energy loss.

Wort cooling systems extract heat from the wort and generate hot water, brine, and propylene glycol solutions, as well as direct expansion of ammonia.

Wort coolers can be classified into: single stage (chilled water only) or multiple stage (ambient water, brine). Dimensions of the wort cooler depend on the amount of hot water required in the brewery for the needed fermentation temperature.

The cooling process is quite simple. Wort enters the heat exchanger and cools to a pitching temperature.

Heat exchangers require scheduled cleaning and proper maintenance for optimal heat transfer. The wort should be properly clarified before entering the cooler to reduce fouling.

Pressure drop in heat exchangers

Fluids need to be pumped through the heat exchanger in most applications. It is essential to determine the fluid pumping power required as part of the system design and operating cost analysis.

The fluid pumping power is proportional to the fluid pressure drop, which is associated with fluid friction and other pressure drop contributions along the fluid flow path. The fluid pressure drop has a direct relationship with heat transfer, operation, size mechanical characteristics, and other factors including economic considerations.

Evolution of plate heat exchangers

Since the introduction in the 1920s for commercial usage plate-and-frame heat exchangers has evolved over the last several decades and various modifications were developed.
Some of these modifications were driven by new strategies for making more compact equipment, some focused on overcoming disadvantages of PHEs, others on expanding the applications spectrum. That resulted mostly in variations of corrugation patterns of plate’s surfaces and altered construction.

Brazed plate heat exchangers are the most compact type of heat exchangers available on a market today. And it is the most efficient one.
Brazed plate heat exchangers are made of a pack of thin corrugated plates that are brazed together to form a durable, self-contained unit. Brazing eliminates the need of frames and gaskets, and results in a unit able to withstand higher pressure and temperatures compared to PHEs. They are compact and lightweight due to absence of frames.

Typical applications of brazed plate heat exchangers include heating and cooling in the process industry, evaporation and condensation in refrigeration systems, and other HVAC installations.

Classification of heat exchangers according to transfer process

There are 2 major categories:
1) Indirect contact type;
2) Direct contact type.

Indirect Contact Type Heat Exchangers

In this type of heat exchangers, the fluid streams remain separate, and the heat transfer takes place continuously through a separating wall. There is no direct mixing of the fluids because each fluid flows in separate fluid passages.


Direct Contact Type Heat Exchangers

In this type of heat exchangers, the two fluids are not separated by a wall. Here, closer temperature approaches are attained and the heat transfer process is also accompanied by a mass transfer.

Compact heat exchangers

Compact heat exchangers are used in a wide variety of applications. Typical among them are the heat exchangers used in air conditioning, beer and wort chilling, solar and geothermal systems, waste and process heat recovery. The need for light-weight, space-saving, and economical heat exchangers has driven the development of compact surfaces.

Specific characteristics of compact heat exchangers include the following:
- a high heat-transfer surface area per unit volume;
- fluids must be clean and relatively non-fouling because of relatively small flow passages and difficulty in cleaning;
- pressure drop consideration;
- operating pressures and temperatures are limited to a certain extent compared to shell and tube exchangers due to joining of the plates by brazing;
etc.

Use of Brazed Plate Heat Exchangers in Solar Heating Applications

Owing to its advantages, brazed plate heat exchangers have become extremely popular in domestic heating applications. Especially in domestic solar heating setups owing to it low cost, low maintenance and high efficiency.

One of the most important factors in determining the viability of a solar heater is its heat transfer efficiency. In simple terms, a good solar heater is one, which is able to transfer maximum amount of heat from the captured sunlight to the inner loop. A brazed plate heat exchanger is ideally suited for this purpose since it occupies much less space, is far more efficient and cost effective than other heat exchangers and is easy to maintain and clean.

Brazed plate heat exchangers in combination with domestic solar panels can be used for:
1. Supplying hot water
2. Heating radiant floors
3. Heating radiant walls
4. Heating water in swimming pools and spas

In all of these applications, solar energy is trapped by a solar panel that transfers the heat to the outer loop. This heat is then collected by a brazed plate heat exchanger where heat is transferred from the outer loop (from the panel) to the inner loop. The heated liquid of the inner loop can now be circulated through a water heater to heat water for domestic supply or passed through radiant walls and/or floors for domestic heating or passed through a swimming pool or spa for heating the water.

Brazed plate heat exchangers can easily handle high temperatures and pressures associated with the latest solar system designs and also keep the domestic water loop in complete isolation with the solar loop. This ensures complete safety of the system as well as long life.

Read more at: http://www.brazetek.com

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Use of Brazed Plate Heat Exchangers in Hydronic Heating Applications

Looking for an efficient, compact and low cost brazed plate heat exchanger to fit your application? We have the solution!

Brazetek heat exchangers are engineered and manufactured utilizing the latest technological advancements and highest quality materials, and can be used for a variety of applications. From radiant heating and snow melting, to solar and hot water heating – we have the right model to fit your needs.

Technology:
To assure the highest level of performance, stainless steel plates are vacuum brazed together to withstand high pressure and temperature variations. The unique design of the plates allows the brazed plate heat exchanger to operate with turbulent flow, providing the maximum thermal efficiency. Such design helps to keep particles in the liquid in constant suspension and prevents them from settling, creating a self-cleaning effect.
Every unit is pressure tested and leak tested to ensure uninterrupted performance and long life.

Applications:
Radiant Heating Outdoor
Wood Stove Domestic
Hot Water Heating
Snow Melting
Solar Heating

Advantages:
Compact size
High heat transfer efficiency
Quick and easy installation
High corrosion resistance
Self-descaling design

We carry an extensive inventory of various models of brazed plate heat exchangers and in most cases can ship the same or next business day.

You can find more information at http://www.brazetek.com

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