Indirect Water Heaters (How They Work and Why You’d Want One)
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How an Indirect Water Heater Works
There may be affiliate links in this content, so please be aware of that. This means that, at no additional cost to you, we may gain a small fee on purchases made via our links and advertisements. Prior to making a purchase, you should be aware of the following facts. 1.
Indirect vs Direct
Due to differences in the way efficiency is evaluated and compared between direct and indirect models, it is impossible to determine which is the more efficient of the two types of water heaters in this situation. It may be claimed, however, that ordinary direct water heaters have a minor advantage over indirect water heaters since there is always some heat loss when water is transported over a long distance. Indirect heaters make up for this by having fewer parts that are exposed to the naturally corrosive substances contained in tank water and by not requiring an additional source of energy.
Also see: Best Residential Water Heaters for more information.
Indirect vs Tankless
One of the most noticeable differences between an indirect heater and a tankless heater is the presence or absence of a tank. A tankless water heater is less susceptible to concerns such as restricted hot water supply and the need for flushing that are common with indirect water heaters. Depending on its rating, tankless water heaters can deliver an unlimited amount of water at a specific flow rate (gallons per minute). A direct water heater, on the other hand, may supply endless hot water every minute up to the maximum number of gallons the tank can contain.
This cost is heavily influenced by the amount of water used and how effectively the indirect heater’s tank is insulated.
If you have a big home, you may combine the two by installing on-demand or smaller tankless units in high-demand areas like as the kitchen to offset the demand in the rest of the house.
Why Should I consider an Indirect Water Heater?
Indirect water heaters make use of an existing heating source to generate electricity, which allows them to save a significant amount of money over time. A direct type requires less maintenance since it has fewer moving components, and they often have better insulation, which eliminates the need for a water heater blanket in some cases. Because they do not require a flue or a separate gas line, an indirect heater that takes advantage of a gas-powered boiler will be significantly more energy efficient (although this does not apply to electric-powered systems, obviously).
A tankless type is self-sufficient in terms of power and fuel, but it receives heat from a secondary furnace or boiler.
Meanwhile, an indirect heater will continue to draw energy from your boiler even during the summer, but the boiler will only operate when necessary, allowing you to save money on energy throughout the year. Hyperthermic Radiant Floor Heating Systems (Pros and Cons, as well as Pricing)
When an Indirect System isn’t Viable
One of the major disadvantages of indirect water heaters is their inability to be retrofitted into any type of housing. For example, forced air furnaces will not be able to heat the exchange pipes because of the high temperature. They can also be a terrible choice for houses where just a small amount of hot water is required, as you will still be responsible for maintaining a huge tank of hot water (usually at least 30 gallons). In such households, an on-demand solution is significantly more efficient.
Can I Install an Indirect Water Heater Myself?
Installation of a direct water heater can be very similar to that of a tankless water heater, and similar complications might develop. However, the key distinction is that the exchange components will require some additional knowledge and expertise to correctly configure. Hiring a professional would assist you in achieving maximum efficiency. If you have previous expertise with complimentary systems, you may be able to install the tank yourself as well.
Image courtesy of supplyhouse.com Water heaters are often overlooked by homeowners because they are located in an inconspicuous location (such as the basement or a rear closet), and they are rarely used. The majority of people simply take it for granted that whenever they turn on the shower or start the dishwasher, hot water will be ready and waiting for them. However, whether they like it or not, when an existing hot water heater malfunctions, even the most uninvolved homeowners must overcome their inertia and become acquainted with the available product options.
The bad news is that, without the assistance of a professional, it can be difficult to establish which of the many different types of water heaters would be the most appropriate for your needs.
Renewed Interest in Indirect Water Heaters
It has been decades since indirect water heaters first appeared on the market. However, with increased environmental awareness and rising energy costs, indirect units are gaining in favour once again nowadays. Why? In certain regions of the country, indirect water heating may provide a tremendous one-two punch in terms of energy consumption reduction and cost savings for households that install it. In fact, according to the Department of Energy, indirect water heaters are “the least expensive way of supplying hot water” to the point-of-use fixtures that you use on a daily basis, numerous times a day, under ideal conditions.
Image courtesy of supplyhouse.com
How Indirect Water Heating Works
The first thing to understand is that an indirect water heater is nothing more than a well-insulated storage tank that contains a helical heat exchanger, but a less frequent design depends on a tank-in-tank arrangement. However, in any instance, the “indirect” unit does not generate its own heat; instead, it relies on the heat generated by the boiler. An indirect water heater is connected to the boiler by a closed-loop water pipe, which allows hot water to be sent to the boiler in a normal configuration.
To put it another way, the boiler does all of the work, while the indirect heater does nothing more than assist the flow of heat.
When to Consider an Indirect Water Heater
If you don’t already have a boiler in your house, you may stop reading this right here and save time. “Indirect water heaters make sense only if you require a boiler for space heating,” says Daniel O’Brian, a technical consultant at SupplyHouse.com. Due to the dominance of forced-air HVAC equipment on the market, boilers are becoming increasingly rare. The boiler runs both systems when you install an indirect unit, heating both the house and the water. This is especially true if your home is one of the few that has hydronic baseboard, radiator, or in-floor radiant heating.
+ In the summer, the issue becomes a little more problematic, not the least because homeowners aren’t used to the boiler running when the house doesn’t need to be warmed up anymore.
Indirect Water Heaters vs. Tankless Water Heaters
There are several types of water heaters that may be operated on demand, and indirect water heaters are one of them. Tankless water heaters, as they are popularly called, are another sort of water-heating technology that does the same purpose. The most important contrast is that the efficiency of an indirect water heater is equal to the efficiency of a boiler, and boilers generally exceed most water heaters in terms of energy efficiency. A tankless unit with an efficiency rate of 80 percent or a conventional unit with a rate of 60 or 70 percent is significantly less efficient than a high-performance boiler capable of attaining 96 percent efficiency.
Installing an Indirect Water Heater
In the event that you are considering installing an indirect water heater in your house, O’Brian highly advises that you speak with a professional about your options. Even while certain parts of the job may be completed by the homeowner, properly sizing an indirect water heater requires a series of sophisticated calculations that are best left to the hands of a qualified and experienced installation. It goes without saying that hiring a contractor and acquiring an indirect water heater aren’t inexpensive endeavors to undertake.
- In addition, because they have fewer moving components and utility connections—as well as no exposure to combustion—indirect water heaters tend to live far longer than other types of water heaters.
- “If you have a boiler or intend to install a boiler, an indirect unit stands out as an obvious alternative” for dependable, cost-effective water heating, whether you’re replacing a damaged water heater or simply want to upgrade, O’Brian says.
- You’re not sure where to begin?
- Don’t worry, if you have any concerns at any point along the journey, customer support representatives are always there to assist you.
Image courtesy of istockphoto.com Consult with a professional Identify qualified plumbing professionals in your area and receive free, no-obligation quotes for your plumbing project.+
HTP – Indirect Water Heating
Indirect tanks are used as a component of a combined heating system to provide heat. These water heaters heat the water by utilizing the space heating system of the residence. High-efficiency indirect water heaters from HTP are constructed of high-quality stainless steel components, resulting in efficient heat transmission and a longer tank life. A boiler is required for indirect water heaters (sold separately). A boiler is used in combination with one of these water heaters to heat the water that is passed via a heat exchanger in the storage tank.
HTP’s Storage Tanks are designed to expand the storage capacity of any hot water distribution system.
These units are constructed of high-quality stainless steel to ensure that they are corrosion-resistant and long-lasting.
When this water is depleted, cold water is introduced into the tank via the bottom, ensuring that the tank is always filled.
What Is an Indirect Water Heater?
An indirect water heater is one of the most efficient methods to heat the water in your South Hadley, MA-area home – but the majority of people aren’t familiar with this high-efficiency alternative. This is how it works: instead of heating water with a separate burner, like a typical water heater would, an indirect water heater uses the heat generated by your boiler or furnace to also heat water for your faucets and appliances. When you operate your heating equipment in this manner, you effectively receive free hot water while it is in operation; when you consider that anywhere from 16 to 20 percent of the energy you consume each month is spent on heating water, this is a significant savings.
Others are as follows:
- The fact that there are fewer parts to maintain– When you combine water and space heating, there is just one burner to maintain. Faster-heating water– Because they employ the high Btu output of the furnace or boiler as a heat source, indirect hot water heaters often have faster recovery rates (the amount of time it takes to re-heat a tank of water) than traditional water heaters. Greater durability– Because an indirect heater does not use a direct flame, stress in the heater is greatly reduced, resulting in a very robust heater with a long life expectancy.
Mass Save incentives for indirect water heaters and more!
If you’re thinking about installing a propane-fired indirect water heater in your house, now is an excellent time to do it because of a Mass Save incentive that may save you up to $400 on the cost of the installation. * Just like with any other piece of equipment we sell, we’ll get your indirect water heater up and operating promptly and accurately so you can start reaping the financial benefits of this smart, money-saving option right away. Would you like to save even more money? The subsidies offered by Mass Save are not restricted to indirect water heaters!
Get in touch with us right now to learn more about these fantastic incentives!
Get in touch with FSi now to receive a FREE, no-obligation quote on high-efficiency propane equipment installations for your Massachusetts residence!
* A propane-fueled heating system must be used in conjunction with an indirect water heater. It is necessary to replace an existing freestanding or tankless water heater. Solar-powered storage tanks are not eligible for this program. For further information, please contact us.
How Do Indirect Water Heaters Work?
System for supplying domestic hot water is one of the most crucial and fundamental equipment required by modern life. There are many different DHW system configurations available, each with its own set of performance characteristics, and there are also many different heat sources to choose from. It is critical to consider energy efficiency while designing any system, regardless of its configuration: Increased efficiency comes at a greater cost, but the additional expense is recouped many times over the course of the heater’s service life in the form of energy savings.
It is the last form of water heater that will be discussed in this article: tankless coil and indirect water heaters.
|Type of DHW System||Description|
|Conventional Storage Water Heaters||Uses a reservoir (storage tank) that is filled with hot water to supply it whenever needed.|
|Tankless or Demand-Type Water Heaters||Heats water directly as it flows through the unit, without using a storage tank.|
|Heat Pump Water Heaters||Uses an inverse refrigeration cycle to heat water. The heat is obtained from outdoor air or from groundwater, and supplied to the water used by plumbing appliances.|
|Solar Water Heater||Uses a solar collector to heat water, without consuming fuel or electricity. Depending on roof elevation, there may be a small pumping cost.|
|Tankless Coil and Indirect Water Heaters||Uses the space heating system for the domestic hot water system.|
What are the Most Common DHW System Configurations?
Commercial water heating (apartments, restaurants, hotels, and other commercial establishments) is almost always done in one of two ways in the boiler room: either a direct-fired boiler or an indirect-fired boiler.
- The first form of water heater arrangement is what we refer to as a normal tank-type water heater system. It is comprised of a huge commercial water heater or a number of smaller water heaters that are adequately scaled for the purpose. The second frequent arrangement is a boiler (either water or steam) that works in conjunction with a heat exchanger and a hot water tank, which is referred to as an indirect hot water heater system. The commercial boiler in this system heats the air in the building while simultaneously supplying hot water to the building’s taps and fixtures through a heat exchanger, which is located outside the building. During the colder months, when the heating system is used often, indirect water heaters perform at their best
- On the other hand, during the summer months, the space heating boiler is obliged to function at a reduced capacity anytime hot water is required.
Water heaters that are fuelled by natural gas, oil, propane, or electricity are called indirect water heaters (whicheverheat sourceis used by the space heating boiler). In addition, an indirect water heater can be used in conjunction with a solar collector to provide any additional warmth that cannot be provided just by solar radiation. It is primarily dependent on two criteria for the efficiency of indirect-fired water heaters: the efficacy of the tank’s insulation and the efficiency of the boiler to which the water heater is attached.
Operating Principle of Indirect Water Heaters
Indirect water heaters take advantage of a space heating boiler that is already in operation in order to keep your building comfortably warm. This tank is positioned adjacent to the boiler and is connected to both pieces of equipment by a closed water loop that runs between the two pieces of equipment. After entering the indirect water tank, the pipe is twisted around like a coil to increase the heat transfer area, and then it is twisted around again to exit the tank. Thus, hot water is circulated from the boiler via the coiled pipe in the indirect tank and back out to the boiler by this process.
Subtypes of Indirect Water Heating Systems
There are three types of indirect water heating systems, each of which may be further subdivided based on how they treat the water that is sent through them.
- When it comes to the utilization of a hot water tank, storage tank systems are comparable to conventional water heaters. Instead of using a direct heat source to maintain a high temperature in the tank, water is continually exchanged between the tank and the heat exchanger to maintain the desired temperature. They are most suitable for situations where huge amounts of water are utilized, but when demand is sporadic
- For example,
- In situations where hot water demand is continuous over a long period of time and there is no need to maintain a tank filled, tankless systems are preferable to traditional tank systems. Because there is no need for a storage tank, this system architecture is more cost-effective, and it should be adopted wherever possible.
- Using a hybrid tank-tankless system is a good option when two different water temperatures are required in the same building for two distinct uses. Alternatively, a storage tank system might be utilized to deliver water at one temperature while the water from the tank is recirculated through the tankless heater to supply water at an even higher temperature.
Sizing an Indirect Water Heater
In order to properly size an indirect water heater, it is necessary to first calculate the demand for hot water, as well as how that need fluctuates from hour to hour. The overall demand defines the needed capacity of the indirect water heater, while the hourly behavior decides whether or not it is practical to utilize numerous units of the same kind. During peak hours when demand for hot water is very strong, the total heater capacity required may be far in excess of what is really needed to meet demand.
As an alternative to utilizing a huge and expensive heater that only runs during peak hours, it is more cost effective to fill a storage tank with sufficient hot water in advance, using smaller units.
Sizing Formula for Heat Input
The following information is necessary in order to determine the heat output of an indirect water heater:
- Flow rate (gpm)
- Hot water temperature (degrees Fahrenheit) required
- Supply water temperature (degrees Fahrenheit)
When the above-mentioned date becomes accessible, the following formula is applied:
- It is calculated as follows: Heat output (BTU/h) = Temperature increase (°F) multiplied by flow rate (gpm) multiplied by specific heat (BTU/gal°F)
Consider the following information as an illustration:
- Specific heat = 8.33 BTU/gal°F at the required temperature of 140°F and the supply temperature of 40°F
- Required flow rate = 300 gpm
- Supply temperature = 40°F
Based on the information shown above, the heat input necessary for the water is as follows:
- 249,900 BTU/h is the heat output when the temperature is 100°F and the flow rate is 300 gpm.
This, on the other hand, is heat that has been delivered to the water. In order to account for the efficiency of the indirect water heater, which is important because no system is completely faultless, The efficiency of the system is assumed to be 80 percent.
- Heat input = Heat output / efficiency = 249,900 BTU/h / 0.80
- Heat input = 312,375 BTU/h
Sizing an Expansion Tank
A check valve, pressure reduction valve, or backflow preventer may be installed in the cold water supply line leading to the indirect heater, resulting in a “closed system.” In a closed system, the expansion of heated water can result in pressure being built up, which can cause the T P (temperature and pressure) relief valve to weep or discharge water. An expansion tank must be put in the cold water supply line in order to prevent this from happening. The expansion tank should be 10 percent of the total capacity of the water heater, or according to the manufacturer’s specifications.
Indirect Water Heater Benefits
Installing an indirect water heater in order to create a combined system is a reasonable option to explore if you already have a large boiler in operation.
- Installing an indirect water heater in order to create a combined system is a reasonable option to explore if you already have a big boiler in service.
Because they are exposed directly to a flame at the bottom of the tank, conventional water heaters deteriorate more quickly than other types of heaters. Aside from that, they must deal with flue gases as well. When exposed to high temperatures on a regular basis, welded joints experience expansion and contraction as well as mechanical stress. Eventually, welded seams begin to split open, and it is at this point that a replacement is necessary. When using an indirect tank, the temperature disparity is significantly reduced.
Because there is no frequent thermal expansion when a coiled pipe is used within an indirect tank, the mechanical load on the tank is reduced as a consequence.
Points to Consider for Indirect Water Heaters
Whatever type of water heating system you pick, there will always be a range of fees to take into consideration. You must consider the costs of additional piping and pumps, as well as the electricity required to power those pumps, when choosing a combination system, even if the boiler is already installed in your building. These costs are in addition to the cost of the indirect tank itself. The combination system, on the other hand, should continue for a long time after the original expenditure.
If your boiler fails, you will be without space heating as well as domestic hot water for several hours.
Idealistically, the boiler should be able to run at a fraction of its maximum capacity throughout the summer – make sure it is not set to maximum capacity when only the residential hot water load is present.
Only an expert can do a precise analysis of your heating loads in order to assist you choose which configuration is the best match for your particular application.
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What is the most efficient water heater for domestic hot water?
Providing domestic hot water (DHW) to a home can be accomplished in a variety of ways. In the event that you are replacing an existing water heater, employing the same sort of system that is presently in place may or may not be the best option for you. In that case, which water heater is the most energy-efficient for your household? There are several factors to take into consideration. A skilled plumbing or heating specialist will be able to provide an informed recommendation based on the specifics of your property and your requirements.
The most common types of domestic hot water heaters:
- Hot water heaters in the form of tanks (electrical, gas, or oil)
- Tankless water heaters that heat water on demand (sometimes known as “instantaneous” heaters)
- Water heaters that use indirect heat and are linked to a boiler
All water heaters provide the same function: to heat water that is used in showers, sinks, dishwashers, and washing machines, among other applications. Water heaters are considered to be a part of the piping system. Your home’s boiler operates on the basis of a hydronic system, which provides heat to the rest of the building. Heaters are an integral element of the heating system. Water heaters and boilers are two different types of equipment that are used to service two different types of systems.
Known as combi boilers, these boilers will be discussed in further detail in a subsequent article.
The pros and cons of tank-style and tankless water heaters are both discussed in detail below.
These water heaters are sometimes referred to as “indirect” or “sidearm” tanks by heating specialists.
It is assumed that you already have a hydronic heating system and are debating whether to purchase a tankless water heater in addition to your hydronic system or whether to add an indirect tank to your current heating system for the purposes of this essay.
Advantages and disadvantages of tankless water heaters
Tankless water heaters are smaller in size than traditional tank-style water heaters and hence take up less space. Tankless water heaters, in fact, may be put on the wall due to their compact size. Tankless water heaters also waste less water because they only heat water when it is required, and they reduce the standby losses involved with maintaining a tank full of hot water. Tankless water heaters have a number of disadvantages, including the possibility of not having enough hot water for households that take several showers and use various hot-water-consuming equipment at the same time.
If the tankless water heater is fueled by natural gas, the unit may have a pilot light, which might consume more energy.
Installing a tankless water heater in addition to a boiler necessitates the installation of an extra gas line as well as the creation of a new wall or ceiling penetration for the water heater’s venting.
What about indirect water heaters?
Indirect water heaters, when used in combination with a boiler, may supply nearly endless amounts of hot water for home use. The recovery rates of these water heaters are far faster than those of rival tank-style water heaters, ensuring that there is always enough of hot water available for your busy lifestyle. What is the operation of an indirect-fired water heater? It is, in fact, rather straightforward. Your boiler boils water and distributes it throughout your home in order to provide heat for the entire building.
- An indirect tank is basically a vessel that has been well-insulated and has a heating coil within it.
- Unlike direct tanks, which contain an electric element, indirect tanks do not require any extra venting.
- It is also possible to incorporate an indirect tank into your boiler system, independent of the fuel that is being used by the boiler.
- The amount of hot water stored is determined by the amount of hot water utilized in the household.
Not all indirect tanks are created equal!
The capacity to resist corrosion and the level of insulation provided by an indirect water heater are the two most important variables that influence the quality and efficiency of the unit. A) The ability to resist corrosion and B) the level of insulation provided by the unit Water that is hard and/or corrosive is the number one adversary of any water heating appliance. Despite the fact that water quality varies considerably across the country, the worse the quality of the water in a given place, the shorter the service life of a water heater will be.
The degree to which an indirect tank is properly insulated or inadequately insulated has a significant impact on the efficiency of the DHW system. The greater the amount of insulation on a tank, the less “standby heat loss” it will have, resulting in cheaper energy bills.
The thermoplastic and hydrastone advantage
When it came to choosing a boiler, U.S. Boiler Company focused on two factors: the capacity to tolerate corrosion and the requirement for high levels of efficiency. TheAlliance SLandAlliance LThigh efficiency indirect-fired water heaters outperform the competition in both categories. The Alliance SL (which stands for stone-lined) was particularly developed and constructed to deal with harsh water. Stone-lined water tanks are not a new concept, and they have shown to be effective in protecting water tanks from corrosion for many years.
- Actually, it is not rare to locate one that has been in operation for more than 30 years!
- This 1/2″ tank liner, which is made of a proprietary substance that is comparable to cement, protects the exterior steel of the tank vessel from corrosion caused by the corrosive action of water.
- After losing its oxygen content, this water transforms into inert, non-corrosive water, which subsequently serves as a protective barrier between the hot water supply and the steel tank.
- The Alliance LT is equipped with a double-bonded thermoplastic tank liner that is exclusive to the company.
- The tank’s thermoplastic design ensures that it will not rust, and the double-bonded liner ensures that it will continue to operate during its extended service life.
Efficiency through insulation
When it came to choosing a boiler, U.S. Boiler Company looked for two things: the capacity to endure corrosion and the requirement for high levels of efficiency. Alliance SLand Alliance LThigh efficiency indirect-fired water heaters outperform the competition in both categories. The Alliance SL (which stands for stone-lined) was particularly developed and manufactured to deal with hard water. Stone-lined water tanks are not a new concept, and they have shown to be effective in protecting water tanks from corrosion for a very long time.
- One that has been in service for more than 30 years is not unusual.
- Tank liners are made of proprietary materials that are similar to cement and are designed to protect the exterior steel of a tank vessel from corrosion caused by water.
- After losing its oxygen content, this water transforms into inert, non-corrosive water, which subsequently serves as a protective barrier between the hot water supply and the steel storage tank.
- The Alliance LT is equipped with a double-bonded thermoplastic tank liner that is exclusive to the Alliance Group of Companies.
- The tank’s thermoplastic structure ensures that it will not rust, and its double-bonded liner ensures that it will continue to operate during its extended service life.
A combination of Hydrastone and thermoplastic liners ensures that each device is so robust that it is covered by a complimentary 10-year guarantee.
Further indirect water heater advantages
For example, unlike many other water heaters, the Alliance SL and Alliance LT do not have any anode rods, which are generally employed to assist prevent corrosion within the water heater tank. The usage of anode rods might result in the stench of rotten eggs emanating from tap water, and these sacrificial rods must be replaced on a regular basis. The Alliance SL and Alliance LT water heaters have one of the fastest recovery rates in the industry because to the design of the heating coil within the water heaters.
- In a 360-degree pattern across the heating coil, the perforated diffuser sprays cold water through the holes.
- According to research, this innovative design has been shown to reduce recuperation time by more than 15%!
- All heat coil connections are positioned on the top of the tank for the sake of accessibility and simplicity of maintenance.
- In the long run, this will result in lower maintenance expenses.
- Please refer to the product data literature for further information.
Indirect Water Heaters: A Boiler Briefing
Water heating in commercial applications (aka companies such as restaurants, hotels, and apartment complexes) is still dominated by what we term a traditional tank-type water heater arrangement in the “boiler room,” which is where the water is heated. Although you may be familiar with the operation of a tank-type water heater from your own company or home, there are several variances among the various types of commercial water heaters, making this sort of system a highly adaptable alternative for a wide range of applications and needs.
Despite the fact that it is still the most frequent configuration, it is not necessarily the only choice available for delivering hot water to your faucets.
The Heating Boiler and Its Loyal Sidekick, The Indirect Tank
It is beneficial to have some basic understanding about boilers in order to comprehend how this system operates. Boilers, like water heaters, create hot water, but they do not have the ability to store it. The hot water (or steam) that they produce may be utilized for a variety of applications, the most common of which is space heating (akahydronic heating). Hydronic heating boilers that are simply used for space heating do not require a location to keep hot water since the hot water is pumped out into the system to heat the building instead, with the heat being distributed throughout the structure using radiators in most cases (known asradiant heat).
(this is known as aclosed-loop system). Whenever a boiler is utilized to provide both hydronic heating and water heating, the system is referred to as a combination system. When it comes to combined heating systems, there are two essential components:
- A heating boiler that uses hydronics (hot water or steam). The principal component of this system is responsible for delivering heating for the building’s interior. Depending on your use and setup, commercial boiler sizes might range from 2′ by 2′ to more than 5′ tall and more than 8′ long. An indirect water heater tank for the purpose of providing domestic hot water to the building’s occupants. An indirect tank is physically similar to a regular water heater, but it lacks the mechanical components necessary to heat the water on its own, necessitating the use of a boiler to be effective.
Therefore, a heating boiler is a necessary precondition if you are considering using an indirect water heater for your household hot water needs. As with a motorbike sidecar, an indirect water heater draws power from the primary appliance in order to provide an additional bonus feature. They are called indirect water heaters because they do not heat the water directly, as do normal water heaters, and hence do not have their own controls. However, they are much more than merely storage tanks. Similarly to a regular water heater, an indirect water heater has its own cold-water input and is filled with clean, drinkable water from the municipal water system after being turned on.
From the boiler, a pipe travels into the indirect tank, where it links with a heat exchanger coil, which is just a metal pipe coiled around like a corkscrew within the tank, surrounded by the household water that has to be warmed up.
(See illustration.) Please understand that in these types of combination systems, the water that is heated directly by the boiler in order to heat a building and the hot water that comes out of the faucets or runs through the dishwasher are not the same; in fact, those two separate streams of water never come into contact with one another.
- However, the primary loop of water is not only utilized for hydronic heat, but it also links to the secondary loop, which is used to heat the domestic, or potable, water that is held within the indirect tank.
- Consequently, the water in this secondary loop is continually heated by the boiler to near boiling temperature before flowing into the indirect tank and via the coiled corkscrew-like heat exchanger pipe included within the tank.
- The coil design provides more surface area, allowing for more heat transfer, ensuring that the water kept in the indirect tank becomes hot enough to give enough of domestic hot water for sinks, dishwashers, and faucets around the house.
- (In reality, an indirect tank is a “hot water heater,” which uses hot water to heat cold water!
The Requirements of a Combination Heating System
The benefits of an indirect water heater system are mostly related to energy efficiency, affordability, and a smaller footprint; however, the feasibility of a combined system is largely dependent on your existing system’s capabilities. A few paragraphs ago, we made the comparison that adding an indirect water heater to a boiler was similar to adding a sidecar to a motorbike in order to obtain more utility. Let’s take it a step further to better understand why indirect water heaters are still considered a niche product in today’s market.
- Furthermore, if you do not have a hydronic heating boiler, an indirect water heater will have no heat source with which to connect, rendering it completely ineffective.
- As a result, if your building is already equipped with a boiler for hydronic heat (as is commonly the case in apartment complexes), adding an indirect water heater to create a combined system may be a cost-effective and energy-efficient way to heat your water.
- Simply said, not all hydronic boilers are efficient enough to be used for numerous applications without sacrificing efficiency.
- As a general rule, the ideal time to start looking at a combination system is when you’re shopping for a new, higher-efficiency hydronic boiler, whether to replace an older existing unit or to build a new home from the ground up.
An indirect tank is an affordable addition that might potentially save you money in the long run by enhancing the efficiency of your water heating operations. If you’re starting from scratch and building a new boiler system, an indirect tank is a worthwhile investment.
The Benefits of Multitasking
A new indirect water heating system includes the installation of additional pipes and pumps, as well as the purchase of energy to power those pumps and the purchase of an indirect water heating tank. Having said that, after you’ve made the initial investment, a combination system may last for a lengthy period of time. Boilers, particularly the newer modulating types that allow changeable settings to prevent being overworked, are built for long-term operation, which means you’re already getting a lengthy service life out of that piece of equipment.
- The following are the reasons.
- The heated gases rise to the surface of the water heater through a series of exhaust flues located within the unit.
- When the building has used up all of its hot water, the water heater tank is replenished with new cold water from the outside, which is then heated up for the next cycle of usage.
- At some point, the high heat exchanges deteriorate the water heater tank, and the welded seams begin to fail, necessitating the need for replacement.
- However, even though the hot boiler water flows through the coiled pipe at a sluggish pace, it heats the water in its immediate vicinity (within the indirect tank) rather fast.
- Because of this, the tank’s thermal expansion is less dramatic, resulting in less stress on the tank itself.
- In spite of the fact that many high-efficiency water heaters achieve their efficiencies via the use of comparable technologies, such as coiled heat exchangers, it is crucial to study all of your alternatives in order to select the best choice for your building and needs.
Furthermore, because of the high BTU output of the boiler, you can frequently get away with using a smaller indirect hot water tank than you would with a traditional water heater, which compensates for the loss of storage space created by the boiler.
However, it is crucial to note that indirect water heaters are most useful when used in conjunction with the newer, high-efficiency modulating boiler models, for a variety of reasons, including the following: Because these high-efficiency boilers attain efficiency ratings between 90 and 99 percent, they are capable of performing many functions, such as providing both heat and hot water while still saving you money on your energy cost.
However, the modulating capability of these boilers is another important feature in maximizing the efficiency of a combined system.
At be more specific, this implies that during warm weather, when you would not be using your boiler for heat, the boiler may be set to a low setting while merely producing hot water, saving you money.
The efficiency of the boiler has a significant influence on whether it is worthwhile to use an indirect water heater over a normal water heater.
The majority of the time, when boilers are used just for hydronic heating, they are turned off during the warmest months of the year.
Furthermore, because a boiler without a modulating burner control is unable to distinguish between the need to fire for heat and the need to fire for hot water, the boiler fires the same amount in both cases and, as a result, will fire more often when utilized for both heat and hot water.
An unavoidable drawback of any combination system is that the hydronic heat always takes precedence over the residential hot water supply.
As a result, if another polar vortex strikes, that boiler may be called upon to provide heat for showers, dishwashers, and other household appliances on a regular basis.
Additionally, when your boiler fails, your entire system falls down, just like when you pick one large water heater rather multiple smaller ones.
Before purchasing a water heating system, it is critical to prepare ahead of time and evaluate your requirements thoroughly.
It is crucial to verify that your boiler and indirect water heater tank are both utilizing softened water, just as it does with tank-type water heaters.
Whenever hard water is heated, the natural minerals present in the water are separated from the water and left behind to adhere to everything they come into contact with.
Wasn’t it mentioned that boilers produce extremely hot water?
Small spaces between the deposits of minerals and sediment create pockets where water vapor gets trapped and pops out, causing minor vibrations.
Because of this, the boiler may bounce up and down, finally resulting in the failure of the heat exchanger.
It will take time for sediment build-up problems to manifest themselves, but by the time apparent symptoms occur, the harm has already been done and cannot be reversed.
For those just getting started with a business water heating setup or those looking to upgrade their existing system, the choice between a regular tank-type water heater and a combined system that incorporates an indirect tank may be difficult.
As a relatively low-cost addition to your hydronic heating system, an indirect water heater tank may be a wise investment since it may help you save money by enhancing the efficiency of your water heating operations in the long run.
Understanding the fundamentals of boilers and water heaters is critical before making a decision on whether or not to replace one or the other.
… You’re not sure where to begin?
Alternatively, you may call our highly qualified personnel at Reliable Water Services (800-356-1444). We’d be delighted to assist you in selecting the most appropriate water heating system for your commercial application.