Indirect boiler with recirculation

Comfort and energy efficiency go hand in hand when it comes to keeping your house warm and comfortable during the winter. Selecting the right heating system is essential to achieving this. Indirect boilers with recirculation have become a more well-liked choice in recent years for efficiently heating homes while optimizing energy savings. This cutting-edge technology is a compelling option for homeowners wishing to upgrade their heating systems because it provides a host of benefits, including increased comfort and efficiency.

What is an indirect boiler with recirculation exactly, and how does it operate then? Indirect boilers use a secondary heat exchanger to transfer heat from a primary heat source, like a furnace or solar thermal system, to the water circulating through your home’s heating system, as opposed to traditional boilers that heat water directly. This indirect approach helps keep the temperature in your house comfortable and consistent while also increasing efficiency.

The recirculation loop, which continuously moves hot water from the boiler through the heat exchanger and back again, is one of the main characteristics of indirect boilers with recirculation. Without the need for a separate storage tank, this continuous circulation helps to reduce heat loss and guarantees that hot water is always available when you need it. You can benefit from a consistent supply of hot water as a result of lower energy use and utility expenses.

Furthermore, recirculating indirect boilers are renowned for their adaptability and compatibility with a wide range of heating sources, such as solar thermal collectors and conventional gas or oil-fired furnaces. With this flexibility, homeowners can select the most economical and environmentally responsible heating solution without compromising comfort or performance.

When compared to traditional heating systems, indirect boilers with recirculation offer greater longevity and dependability in addition to efficiency and compatibility. These boilers require less maintenance and are less likely to break down because they have fewer moving parts and experience less wear and tear. This will ultimately save you time and money. Additionally, a lot of models have sophisticated features like smart controls and modulating burners, which further optimize performance and reduce energy consumption.

All things considered, recirculating indirect boilers are an environmentally friendly and astute way to heat your house effectively and comfortably. These cutting-edge systems provide homeowners looking for dependable and affordable heating solutions with consistent warmth, reduced energy costs, and peace of mind by utilizing the power of continuous recirculation and indirect heat transfer.

Advantages Efficient heating, constant hot water availability
Disadvantages Initial installation cost, requires space for installation

Principle of recirculation

A unique outlet for connecting DHW recirculation lines has been added to a lot of these boilers in order to maintain a consistent temperature of heated water. As a result, an extra pipe is installed during system installation to guarantee the medium’s passage through a closed ring and the potential for withdrawal. A DHW recirculation system makes sense if the pipe length exceeds 10 meters. Its basic concept is fairly straightforward, with a few minor construction variations based on the indirect heating boiler piping scheme and the distribution method—collector, two-pipe, or standard—for a given consumer.

With the collector scheme, water travels through the collectors one after the other before returning to the indirect boiler at the system’s beginning. In a system with two pipes, the water flows in tandem with the cold water, but it doesn’t stop at the end user—rather, it loops back to its starting point.

The standard arrangement uses a return line that extends from the farthest water intake to a tee or the tank’s cold line, with a common point at the indirect boiler’s drain valve. As a result, hot water circulates and is delivered to the user with precise parameters.

The return flow contains the hot water recirculation pump installation. A temperature sensor and a timer, which turns on the system’s components typically during the hot water supply’s peak load, control the system.

When a user has secondary energy resources available for the heat supply scheme, such as in an autonomous heat supply system driven by a boiler, they can use indirect heating, wherein some energy is used for the BKNSR and the rest for heating.

The water in the external heating circuit is heated as the heating medium passes through the tank’s internal coil. Following that, water from the accumulator tank enters the DHW system and the cold coolant is pumped to the boiler for a second cycle.

In terms of structure, boiler connections can be made to a number of circuits in the form of coils that draw heat from various sources, including the boiler heat carrier, flue gases, solar generators, and electric TENs.

Capacity calculation and equipment selection

Initially, the heat load for DHW for a specific consumer must be calculated in order to select the scheme and equipment. An improper connection technique could lead to the main and pumping equipment failing or the DHW recirculation system becoming inefficient.

For instance, use SNiP 2.04.01-85 "Internal water supply and sewerage of buildings" to calculate the hot water standards for a family of four.

Based on basic calculations, doing the dishes will need 336 liters of water per week, taking a shower will need 1280 liters, and small actions will need 280 liters, for a total of 2856 liters per week, or 17 liters per hour.

Formula to calculate the capacity:

17˞0.0375=0.637 kW

The heater’s calculation parameters are:

  1. Minimum water consumption 1.5 l/min.
  2. Tank volume – more than 100 liters.
  3. Water heating time up to 2 hours.
  4. Thermal insulation material is polyurethane foam or mineral wool.
  5. Protection elements: valves, temperature and pressure sensors and fuses.
  6. Service life – 10 to 12 years.

We discuss the effective use of an indirect boiler with recirculation in our guide to efficiently heating and insulating your home. With the help of a heat exchanger, this system provides an intelligent way to heat your house by transferring heat from the boiler to the water supply. Recirculation maximizes energy efficiency by returning heated water to the boiler, guaranteeing constant warmth throughout your home. Homeowners can maximize the comfort and economy of their heating systems by making educated decisions based on their comprehension of the advantages and workings of this configuration.

Indirect heating boiler Drazice

In the trade network, there are dependable, practice-tested Drazice indirect boilers with capacities ranging from 80 to 200 liters that do not include heating elements. An external heat energy source with maximum parameters of 110 C and 10 bar is connected to the heater body. Through a spiral heat exchanger with a developed heating surface, heat is transferred.

The boiler comes with a circulation pump, a thermostat to operate a three-way valve, and an outlet temperature regulator.

At the bottom, there is a flange-mounted hatch for maintenance and repair tasks, like clearing the tank of debris and limescale.

Benefits of indirect boilers made by Drazice:

  • durability, the tank inside is coated with nickel-free enamel and magnesium anode for anti-corrosion protection;
  • An additional flange to accommodate an R-series coil;
  • B class energy efficiency;
  • protection against galvanic effect and electrochemical corrosion;
  • control automation for safe operation.

Wiring diagram for the indirect heated boiler with recirculation

An indirect water heater’s connection method is the same as that of a traditional boiler.

The standard unit includes the following components and has a tank-like appearance:

  • cylindrical tank – horizontal or vertical;
  • insulating coating for temperature retention;
  • temperature and pressure sensors;
  • coil – heat exchanger;
  • anti-corrosion protection.

The coils, which are composed of brass or steel, are the most intricate piece of machinery. For uniform heating of the medium that is fed into the tank coil, they are constructed in an intricate arrangement closer to the bottom of the tank. The BKNSR piping is installed in accordance with the drawings, accounting for each unique feature of the heat supply system.

The boiler is utilized in three common installation schemes to create a DHW circuit:

  1. Inclusion of a three-way valve in the scheme.
  2. Placement of a circulation pump with several modes of operation.
  3. Connection via a hydraulic arrow.

Tanks with greater volume are equipped with three-way valves, and the system is computed using the two-circuit heating principle. The three-way valve scheme installs two circulation pumps to distribute incoming medium on heating and DHW flows. Thermostats and automatic medium switches round out the installation.

For items with more than two circuits, such as radiators, underfloor heating, or DHW circuits, hydronic arrows are utilized. With the help of a towel dryer that is installed in the looped circulation loop break and has a pump, it is possible to recirculate water to complete a simplified indirect heating boiler connection scheme. In this instance, the BCNPSR has three connections—two for DHW and one for system makeup—which generates the pressure of the medium flow in a closed circuit.

If the water heater uses a pumpless circulation system, DHW is heated and circulated through a closed loop before being replenished with cold water as it is used up. This three-way thermostatic mixer is used to accomplish recirculation.

Recirculating indirect boilers are becoming a very attractive option for effectively heating and insulating homes. These systems provide increased cost-effectiveness and energy conservation by utilizing the power of recirculation.

Maximizing heat transfer efficiency is one of the main benefits of indirect boilers with recirculation. The hot water circulates between the boiler and a heat exchanger to provide uniform heat distribution throughout the house, guaranteeing warmth and comfort.

Furthermore, these systems are very adaptable and work well with a variety of heating sources, such as geothermal and solar energy. Because of its adaptability, homeowners can tailor their heating solutions to meet their unique requirements and environmental preferences.

By lowering energy use and carbon emissions, indirect boilers with recirculation also support sustainability initiatives. These systems encourage environmentally conscious living and lessen their negative effects on the environment by streamlining heat transfer procedures and making use of renewable energy sources.

All things considered, homeowners looking for economical, environmentally friendly, and efficient heating options would be wise to invest in indirect boilers with recirculation. The future of home heating and insulation is going to be greatly influenced by these systems because of their exceptional performance, adaptability, and sustainability advantages.

Video on the topic

Connecting the indirect heating BOILER. Recirculation system. Hot water in the house.

Boiler piping / Hot water recirculation

Why do you need recirculation of DHW?. Recirculation connection diagrams with indirect heating boiler.

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Sergey Ivanov

I like to help people create comfort and comfort in their homes. I share my experience and knowledge in articles so that you can make the right choice of a heating and insulation system for your home.

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