Thermal unit in an apartment building principle of operation

Our houses turn into our havens from the bitter cold as winter arrives. The thermal unit, a vital component that guarantees our living spaces remain warm and comfortable, is central to this comfort in many apartment buildings. However, have you ever wondered how this system fends off the cold in the background?

The idea underlying an apartment building’s thermal unit is simple yet quite clever. Fundamentally, the system is made to disperse heat in a way that makes every apartment in the building feel warm and comfortable. It uses a centralized heating system in which heated air or water is sent to each apartment through ducts or pipes after being heated by a main boiler or furnace.

When it comes to heating large residential complexes, efficiency is crucial. The temperature inside and outside the building is tracked by sensors and controls built into the thermal unit. Thanks to this clever technology, the system can optimize comfort levels while reducing energy waste by adjusting the heating output based on the current situation. The thermal unit plays an important role in controlling energy bills by adjusting to the outside temperature and the residents’ heating needs.

An important factor in the thermal unit’s efficacy is insulation. Better heat retention from a well-insulated building eases the strain on the heating system and results in lower energy usage. In addition to keeping the cold out in the winter, proper insulation also contributes to year-round comfort levels inside. The thermal unit and insulation have a symbiotic relationship that enables them to jointly produce a warm and energy-efficient living space for building occupants.

1. What is a thermal energy metering unit

A thermal unit is a group of devices whose installation is part of a project that offers energy accounting and regulation, heat carrier volume, parameter registration and control, and other related functions.

An automated module called a heat metering unit is added to the plumbing system to provide accounting information for the project of operating and controlling the heating resources.

1.1 Where thermal units are installed

Heat unit installation and maintenance are typically done in typical apartment buildings that have shared heating systems.

In turn, an apartment building’s heat energy metering units are installed to carry out the following duties:

• checking and regulating the operation of the heat carrier and heat energy;
• check and regulation of hydraulic and heating systems;
• recording of heat carrier data such as temperature, pressure and volume.
• making a monetary settlement between the consumer and the heat energy supplier, after verification of the obtained data has been carried out.

Heat energy metering unit installation

It should be taken into account when installing heating equipment that the users (in this case, the apartment building’s occupants) incur certain financial costs due to the resource consumption of the central heating system in an apartment building.

If competent metering equipment inspection and maintenance, including high-quality installation equipment and pipelines, are provided on time, the apartment building will be able to save costs and maintain the constructed unit’s operability in accordance with the previously designed scheme for a long time.

The thermal unit in an apartment building is like the heart of its heating system, ensuring that every resident stays warm during colder months. Here"s how it works: the unit heats water, which then flows through pipes to radiators in each apartment. As the hot water circulates through these radiators, it releases warmth into the rooms. At the same time, the unit also controls the temperature by sensing when more heat is needed and adjusting accordingly. Insulation plays a crucial role here too, keeping the heat inside and cold air out, making the heating process more efficient and cost-effective. In essence, the thermal unit and insulation work hand in hand to create a cozy and energy-efficient environment for everyone in the building.

2. Device and schematic diagram of the thermal unit

The installation of the thermal unit, which is included in the preliminary project for the communal systems of apartment buildings, consists of a complex set of tools and apparatus. A device of this kind can be used for one or more purposes, like:

1. Measure the quantity and mass of heat energy, its pressure, the temperature of the fluid circulating through the pipeline and the time of operation.
2. Accumulation and storage of this information on a local carrier.
3. Displaying it on the metering devices.

The operation, regulation, and maintenance of apartment building heating equipment are done based on the data that was received.

A meter is an example of a metering device, and its scheme includes:

1. Thermal resistance transducer.
2. Heat calculator.
3. Primary flow converter.

The heat meter’s construction may include filters and pressure sensors, depending on the type of primary converter that was installed (with vortex, ultrasonic, electromagnetic, or tachometric variants of measurement).

The components of the heat energy metering unit are as follows:

1. Shut-off valves.
2. Heat meter.
3. Thermal converter.
4. Mud trap.
5. Flow meter.
6. Thermal sensor of the return pipe.
7. Additional equipment.

In turn, installing the system of heat energy metering equipment in the apartment building necessitates the following essential conditions:

• the necessity to install the metering equipment scheme only at the boundaries of the balance belonging of the pipelines in the places closest to the main gate valves of the heating source;
• prohibition to organize the project of heat carrier for personal needs in the communal heat supply system;
• regulation of average hourly and average daily parameters of the heat carrier are made according to the readings of the metering equipment;
• metering devices are mounted on the return pipelines of the mains and are placed up to the place of connection of the subbit pipeline.

Competent services perform competent installation and operation checks on the equipment in order to realize competent regulation and control over it.

2.1 Who installs and maintains the heat exchanger in apartment buildings?

Apartment buildings have hot water supply (HWS) and central heating (CH), with the main supply pipeline situated in the basements and fitted with shut-off valves. The latter allows the internal heating supply system to be disconnected from the external network.

The thermal unit itself has an elevator-like device built into its design, along with strainers, shut-off valves, control, and measurement devices. Regular maintenance is usually needed, one of which is the strainer, a steel pipe with a diameter of Du=159–200 mm that is used to collect dirt from the main pipeline in order to prevent contamination of heating devices and pipelines.

The locksmiths servicing the residential building install the thermo-node and maintain it, including cleaning it, in accordance with the guidelines set forth by the housing and communal services organization.

Elevator unit of the heating system – principle of operation

Thermal scheme of heating with an elevator unit

The heating system’s elevator unit is a unique construction that serves the following purposes: jet pump or injector functions. Increasing the pressure inside the heating system is the primary goal of the scheme utilizing such a device. i.e., by raising the coolant volume, the liquid circulation through pipes and radiators is improved.

Standard physical laws serve as the foundation for the thermal unit’s pressure increase scheme. In this instance, heated coolant is supplied under pressure from the common boiler room through the central main line, which is connected to the elevator unit if it is detected in the heating system.

Temperature indices within the main heat supply line can rise to +150° C during severe frosts. However, given that water turns to vapor at this temperature, it is physically impossible. On the other hand, in open containers with no pressure, a liquid can change states when exposed to high temperatures. However, the coolant in heating pipes is forced to circulate by circulation pumps, preventing it from vaporizing.

Everyone must know that water temperatures above 100°C are deemed excessively high, and that providing such water to residential buildings is prohibited for several reasons.

• Standard cast iron radiators, which are installed in most old multi-storey buildings, do not tolerate sharp temperature fluctuations, which can cause them to fail. In the best case they will start to leak, and in the worst case cast iron becomes very brittle and easily destroyed.
• Very high temperature of radiators can lead to burns when touching metal elements.
• Recently, the scheme of heating system wiring is made of plastic pipes, which can withstand a temperature of not more than +90 ° C. Consequently, they can melt.

Thus, it is necessary to cool down before directly supplying the heating medium to the apartment. The elevator was created with this purpose in mind. These days, the elevator unit is a crucial component of the thermal system’s architecture. This was brought about by its extremely stable operation regardless of changes in the heating network’s temperature.

Constructional features of the elevator

The following structural components are part of this equipment: liquefaction chamber, jet type elevator, and special nozzle. Apart from the elevator unit itself, however, its piping needs to be done, the main ones being the installation of shut-off valves, pressure gauges, and thermometers.

As of right now, the ability to automatically alter the coolant flow rate in apartment building heating systems is made possible by the increasing popularity of devices with electric actuator nozzle adjustment.

How the elevator functions

The mixing of hot and cooled heat carriers is the foundation for the elevator unit’s operation. The already-cooled coolant that is returned from the radiators is combined with the superheated liquid that is passing through the main line in the elevator chamber. In other words, superheated heat transfer medium combined with water from the return circuit. The elevator can do multiple tasks at once:

• forced circulation system;
• a reservoir in which the heat transfer fluids are mixed.

Despite its straightforward design, the heating system’s elevator unit has a positive attribute in its high efficiency. One more benefit of having such an element is that the device is relatively inexpensive. Furthermore, an AC mains supply connection is not required. Of course, the elevator has drawbacks as well.

• productive operation of the elevator unit can only be guaranteed if every component of the unit is accurately calculated;
• The pressure drop between the main and return lines must not exceed 2 bar;
• absence of temperature regulation at the outlet.

Because of this device’s effectiveness in handling sudden changes in the thermal and hydraulic conditions of the heating system, it is now commonly found in apartment building heating mains.

Common breakdowns of the elevator unit

The primary causes of the heating system elevator’s malfunctions could be clogged nozzles or an increase in the nozzle’s internal diameter. A clogged strainer can also be the source of breakage. regulator setting failure and shut-off valve breakage.

The temperature differential before and after the device can be used to diagnose a heating system elevator unit breakdown. An elevator breakdown brought on by clogging or an increase in the nozzle diameter can be identified if a significant difference is found. But regardless of the malfunction, qualified experts perform diagnostics. The elevator unit is cleaned if there is clogging.

In the event that corrosion has caused the original diameter to increase, the entire heating system will become completely unbalanced. In this scenario, the lower apartments’ radiators will get extremely hot, and the radiators in the rooms on the upper floors will not receive the full amount of heat energy. A new analog with the necessary diameter is replaced in order to solve the issue.

By altering the readings of pressure sensors placed immediately before and after the heating elevator unit, one can identify whether the strainers in the unit are clogged. A tap at the bottom of the strainer is used to release contaminants that are present in the heating system. Should these measures prove ineffective, the apparatus is disassembled and subjected to a mechanical cleaning process.

Alternative variant of the thermal scheme

Modern technologies have made it feasible to replace the elevator with a more sophisticated device that is used in apartment building heating systems. Automated system heating controls offer a full substitute for the conventional elevator unit. Even though it is more cost-effective to use, such a device is much more expensive.

The automated unit’s primary function is to regulate the heating system’s internal temperature and flow rate in response to external temperature changes. A sufficiently large capacity electrical source is required for the operation of such a unit. However, utility companies continue to favor the elevator unit despite all the advancements in heating technology.

These days, heating system elevators with an electric control actuator are common. Furthermore, the coolant flow rate can be adjusted without the need for human involvement. Utility companies do not appear to have any plans to replace this equipment anytime soon, despite its indisputable benefits.

What is the elevator unit of the heating system

Strong boiler houses, or CHPPs, receive heat from a variety of sources, including administrative buildings, multi-story buildings, high-rise structures, and many other consumers. It can be challenging to modify even a fairly basic autonomous system in a private home, particularly if errors were made in the system’s installation or design. However, a big boiler house’s or CHPP’s heating system is far more intricate. Numerous branches branch off of the main pipe, and the amount of heat that each consumer uses and the pressure in the heating pipes vary.

Since the pipelines’ lengths vary, the system must be built to ensure that even the furthest-flung consumer gets enough heat. The need for the heating system to pressurize the coolant becomes evident. As a circulation pump, pressure is generated by the central heating main and moves the water through the heating circuit. When a consumer’s heat consumption varies, the heating system shouldn’t become out of balance.

Furthermore, the system’s branching shouldn’t have an impact on the heat supply’s efficiency. An automated heating system control unit or an elevator unit must be installed at each facility to prevent mutual influence in order for a complex centralized heating system to function steadily.

Heat distribution point of the building

There are three temperature modes for boiler operation that heat engineers recommend using. These modes have been used for many years; they were initially computed theoretically. They guarantee efficient heat transfer over long distances with minimal losses.

The ratio of the supply temperature to the "return" temperature characterizes the thermal regimes of boiler houses:

1. 150/70 – the supply temperature is 150 degrees Celsius and the return temperature is 70 degrees Celsius.
2. 130/70- water temperature 130 degrees, "return" temperature 70 degrees;
3. 95/70 – water temperature is 95 degrees, "return" temperature is 70 degrees.

In actuality, the value of the winter air temperature determines which mode is used for each unique location. It should be mentioned that using high temperatures—particularly between 150 and 130 degrees Celsius—will not prevent burns or other severe effects in the event of depressurization.

Because of the high pressure inside the pipes, the water does not boil even though its temperature is above the boiling point. This implies that in order to provide the required heat extraction for a given building, it is imperative to lower the temperature and pressure. The heating system’s elevator unit, a unique piece of equipment housed in the heat distribution center, is tasked with handling this task.

Design and principle of operation of the heating elevator

The node connecting the supply and return pipes is the focal point of the heating network pipe entry, which is typically located in the basement. This elevator serves as a heating mixing unit for homes. The elevator is constructed as a steel or cast iron structure with three flanges. It is a traditional heating elevator, and the rules of physics govern how it works. A nozzle, an inlet chamber, a mixing head, and a diffuser are located inside the elevator. A flange is used to connect the inlet chamber to the "return".

After entering the elevator through the inlet, the superheated water exits through the nozzle. Bernoulli’s law states that as the nozzle narrows, the flow velocity increases and the pressure decreases. The elevator’s mixing chamber is where the water from the return flow is mixed after being drawn into the underpressure area. In addition to lowering the temperature to the necessary level, water also lowers pressure. The elevator functions as a mixer and a circulation pump at the same time. This is the basic idea behind how an elevator works in a building’s or structure’s heating system.

Schematic diagram of the heat distribution unit

Internal house elevator heating units regulate the coolant supply. The heating system’s primary component, the elevator, must have the following parts installed. Because the piping contains dirt filters that are connected to the "supply" and "return," the regulating equipment is susceptible to dirt.

The piping in the elevator consists of:

• dirt filters;
• pressure gauges (inlet and outlet);
• temperature sensors (thermometers at the elevator inlet, outlet and return);
• gate valves (for preventive or emergency work).

Although this is the most basic version of the coolant temperature regulation scheme, it is frequently utilized as the heat unit’s primary component. Basic node elevator heating controls the coolant’s temperature and pressure within the circuit for all buildings and structures.

The benefits of using it to heat big items, homes, and tall buildings:

1. trouble-free operation due to the simple design;
2. low cost of installation and component parts;
3. absolute energy independence;
4. Significant savings of up to 30% of heat carrier consumption.

Though there are unquestionable benefits to utilizing an elevator for heating systems, there are drawbacks as well:

• The calculation is made individually for each system;
• a mandatory pressure drop in the object"s heating system is required;
• If the elevator is not adjustable, it is impossible to change the parameters of the heating circuit.

Elevator with automatic regulation

There are now elevator designs available with electronically adjustable nozzle cross-section. There is a mechanism in such an elevator that moves the throttle needle. It modifies the nozzle lumen, which modifies the heating medium’s flow rate. The lumen can be adjusted to alter the water’s movement speed. This causes a change in the mixing coefficient between the hot water and the water from the "return," which raises the coolant’s temperature in the "supply." It is now evident why water pressure is necessary for the heating system.

The coolant supply and pressure are controlled by the elevator, and the coolant’s pressure controls the flow of the heated circuit.

Main faults of the elevator unit

A simple elevator assembly is one example of a device that can go wrong. By examining the pressure gauge readings at the elevator assembly’s control points, faults can be identified:

1. Malfunctions are often caused by the clogging of pipelines with dirt and solid particles in the water. If there is a drop in pressure in the heating system, which is significantly higher before the strainer, this fault is caused by clogging of the strainer, which stands in the supply pipeline. Dirt is discharged through the drain channels of the strainer, cleaning the screens and internal surfaces of the device.
2. If the pressure in the heating system fluctuates, corrosion or clogging of the nozzle can be a possible cause. If the nozzle is destroyed, the pressure in the heating expansion tank may exceed the permissible pressure.
3. There may be a case when the pressure in the heating system increases, and the pressure gauges before and after the strainer in the "return" show different values. In such a case the "return" strainer must be cleaned. The drain taps on it are opened, the grid is cleaned, and contamination from inside is removed.
4. If the nozzle size changes due to corrosion, the heating circuit is vertically unbalanced. At the bottom of the radiators will be hot, and on the upper floors are not heated enough. Replacing the nozzle with a nozzle with a calculated diameter eliminates this malfunction.

Distributing devices

When the elevator unit is fully strapped, it can be thought of as a discharge circulation pump that feeds coolant into the heating system at a specific pressure.

The best course of action in cases where the object has multiple floors and consumers is to allocate the entire coolant flow to each consumer.

The manifold, also known as the comb for the heating system, is designed to address such issues. You can think of this device as a vessel. The elevator outlet provides the coolant, which enters the tank and exits through multiple outlets at the same head.

As a result, the heating system distribution comb permits the individual consumers of the object to be disconnected, adjusted, or repaired without interrupting the heating circuit’s operation. The heating system branches’ mutual influence is eliminated when a collector is present. The pressure at the elevator outlet and the pressure inside the radiators are equal.

Column	Description
Thermal Unit	This is the heart of the heating system in an apartment building. It"s usually a boiler or a furnace that heats water or air.
Principle of Operation	The thermal unit heats up either water or air, which then gets distributed throughout the building. In a water-based system, hot water is pumped through pipes to radiators or underfloor heating. In an air-based system, heated air is pushed through vents into each room.

It’s critical for homeowners to comprehend how an apartment building’s thermal unit operates.

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