Unit Heater

Unit heaters are used to provide heating for sports and industrial projects that operate with a central hot-water or steam boiler room. The following sections present the types, the technical specifications, capacity estimation, selection method, and purchase price of unit heaters.

Unit Heater Expert Buying Guide and Price List

Unit heaters receive the hot water or steam (unit heaters or steam unit heaters) for their heating coils from the building's central boiler, usually located in the engine room. They are devices that can heat large spaces, such as sports halls and factories, in the shortest time.

If you have a central heating system in your building, a unit heater with the appropriate power will act as an auxiliary heating device. However, if you do not have a central heating system, you should use gas, diesel, or electric home heaters and/or industrial heaters.

Unit heaters that use electrical energy are a adequate option for people looking for easier ways to provide heating for the hall space. The heat output of a unit heater is often measured in BTU or watts. To choose a unit heater with the appropriate heat output, the size of the space, the insulation of the ceiling and walls, and the weather conditions and use of the desired location should be considered.

The dimensions and volume of the hall are the first parameters that should be considered when choosing the capacity and number of unit heaters; if you have a large space, you will need one or more high-power unit heaters to effectively heat the entire space. Conversely, for small spaces, a smaller unit heater will suffice.

The following are 7 key factors to consider when choosing a hot water or steam unit heater, so stay tuned…

Unit Heater Approximate Capacity Calculation

You should calculate the approximate capacity of the unit heater for a space based on a few factors:

1. The weather conditions of the area (temperature outside in the winter)
2. The dimensions and usage type of the area (temperature inside)
3. The type of materials used in the construction of the area

You can consider the heating capacity of about 250 to 500 BTU/hr per cubic meter of air volume according to the decision of the constructors.
Consider about 250 to 300 BTU/hr per cubic meter for warm cities such as:

• Saudi Arabia: Yanbu, Jeddah, Mecca, Al Wajh, Al Hufuf, Unayzah, Buraydah
• Lebanon: Baslouqit, Bdebba, Baddouaa, Abu Saad, Aassoun, Deir Janine, Halba, Hakour, Haizouq
• Yemen: Ayn Milh, Tarim, Ard al Huwayl, Ard as Suqayr, Bayt al Mudir, Al Ma'shur
• Iraq: Amarah, Nasiriya, Kut, Kerbela, Semawa, Badrah, Rafaei
• United Arab Emirates—UAE: Dubai, Difan, Bida, Ghayl, Uwaynat, Ar Rafa'ah, Lazimah, Adh Dhayd, Layyah
• Qatar: Duha, Al Rayyan, Al Daayen, Al Wakrah
• Kuwait: Jahra, Sulaibiya, Al Wafra, Abdaly, Sabriyah
• Syria: Deir ez-Zor, Al Raqqah, Al Hasakah, Hama, Daraa, Aleppo, Homs, Idlib
• Turkey: Cizre, Urfa, Batman, Siirt, Izmir, Adana, Amasya, Istanbul
• Azerbaijan: Saatly, Sabirabad, Zerdab, Imishli, Beilagan
• Armenia: Armavil, Aragatsotn, Yerevan, Syunik, Tavush, Ararat, Kotayk, Lori

Consider about 300 to 500 BTU/hr per cubic meter for cold cities such as:

• Saudi Arabia: Turaif, Sakaka, Abha, Rafha, Riyadh, Arar
• Lebanon: Baalbek-Hermel, Beqaa, Nabatieh, Akkar, Ain Dara, Beirut
• Yemen: Sa'dah, Dhamar, San'a, Al Mahwit, Al Jawf, Ma'rib, Shabwah
• Iraq: Sulaymaniyah, Dokuk, Nineveh, Kirkul, Saladin, Anbar, Muthanna, Babil, 
• United Arab Emirates (UAE): Al Quwain, Al Khaimah, Fujairah, Ajman, Sharjah
• Qatar: Umm Salal, Al Shamal
• Kuwait: Farwaniya, Al Asimah, Hawalli, Ahmadi, Mubarak Al-Kabeer
• Syria: Damascus, As-Suwayda, Quneitra
• Turkey: Erzurum, Ardahan, Erzincan, Agri, Bayburt, Kars, Karabut, Kastamonu, Bingol, Hakkari, Van, Samsun, Bursa
• Azerbaijan: Kelbajar, Balaken, Gabala, Zagatala, Gahk, Shamkir, Sheki, Oghuz
• Armenia: Vayots Dzor, Shirak, Gegharkunik

Note: These numbers are 100% accurate, and for proper results, the decision of the

7 Factors to Consider When Choosing Unit Heaters

Here are 7 key factors to keep in mind when choosing a unit heater:

1. Pay attention to the dimensions (length, width, and height) of the desired location and calculate the volume of the relevant space completely.
2. Calculate and obtain the required heating capacity for the desired space based on the following method.
3. Determine the type of unit heaters required based on the type of fluid available for heating the environment (hot water or steam).
4. Using the technical specification tables provided for the products at the DamaTajhiz HVAC store, obtain the number and heating capacity of unit heaters (wall or ceiling).
5. Pay close attention to the issue of whether the hot water or steam coil of the unit heaters is connected to the left or right, as well as the working pressure of the coil (especially steam coils).
6. Considering the noisy operation of the unit heater fan at 1400 RPM, it is better to choose a unit heater with a double speed or 900 RPM (but with a higher heating capacity).
7. In some cases, specifically for climates with moderate summer temperatures and a central cooling system (chiller), unit heaters can also be used to provide cooling in the summer. In these cases, in addition to the standard two-row coil, an optional cooling coil and drain tray must be added under the cooling coil of the unit heater.

Unit Heater Heating Capacity Calculation

The following is the formula you need to calculate the thermal capacity of a hot water/steam unit heater:

QT = (U1 x A1 + U2 x A2 + U3 x A3 + … + An ) x ΔT + (V × 0.0749 x 0.24 x ΔT)

• QT: heating load of each unit in kilocalories per hour.
• U1: to Un heat transfer coefficient of each surface between the inside and outside the building in terms of BTU/ft2.hr. °F, which should be determined based on the material of each wall, using engineering reference tables.
• A: is the area of each of the peripheral surfaces of the corresponding unit that transfers heat to the outside of the building. This area (in square feet) includes walls, windows, doors, and ceilings.
• ΔT: the temperature difference between the inside and outside each unit under normal conditions, which is in °F.
• V: Total amount of air infiltrating through door or window seams (CFH) in ft3/hr.
• Constant factor 0.0749: air density in conventional conditions in the English unit system.
• Constant coefficient of 0.24: specific heat capacity of ambient air in conventional conditions in BTU.

In this formula, by calculating all the parameters, you can get accurate results to determine the heating capacity and the number of unit heaters required for your place.

Note: Accurate values of U and A for each of the surrounding surfaces must be considered based on details in each building and engineering tables of the heat transfer coefficient.

Different Types of Unit Heaters

Unit heaters are divided into several for providing ambient heating in terms of installation location, fluid type, and airflow direction.

1. Installation Location: In terms of installation location, unit heaters are divided into two categories: ceiling unit heaters and wall unit heaters.
2. Fluid Type: In terms of the heating fluid, unit heaters are divided into two categories: steam and hot water.
3. Airflow Direction: In terms of air direction, unit heaters can be divided into horizontal airflow and vertical airflow.

Features and Advantages of Unit Heaters

The following are the most important advantages of a unit heater:

• No need for an independent heating system
• Having adequate heating power
• Less space, especially in wall and ceiling models
• Better distribution of hot air in the environment
• High speed in heating the environment
• The ability to install and throw air horizontally and vertically
• Controlling the ambient temperature using an indoor thermostat
• Equipped with hot water or steam coils
  
  

Unit Heater Components and Parts

Unit heaters usually consist of five main parts:

1. The Body: The cubic body of the device is usually made of steel sheets.
2. The Coils: Hot water or steam coil set with heat exchange fins that increase the heat energy transferred from hot water or steam to the air coming out of the unit heater.
3. The Electric Motor: The electric motor can be used to drive the axial fan of the unit heater, and based on the order of the respected buyer and the production of the factory, a single-turn or two-turn electric motor may be used.
4. The Axial Fan: The axial fan, which is actually the ventilation fan of the unit heater, sucks air from the back of the device, passes it through the coils and heat exchange fins of the hot water or steam, and then releases the hot air from the front of the unit heater.
5. The Vanes: The vanes are installed in front of the unit heater and can direct the hot air coming out of the unit heater.

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How Unit Heaters Work

In unit heaters, the required hot water or steam flows from the engine room to the coil of each unit heater by circulator pumps (flow rate and friction head must be calculated by facility engineers).

After hot water or steam enters the finned coils of the unit heater, the air passes through the coil assembly and the heating fins, which are usually 8 fins per inch of the coil, and is then heated by the axial fan or propeller. It is pushed forward and causes the air in the installation area to heat up.

The operation on or off and even the change of the engine speed of the hot air blower unit heaters is regulated by the thermostat installed at the height of 140 cm from the floor of the space and away from the hot air flow of the unit heater or direct sunlight.

The amount of air ejection and the volume of air output in unit heaters are also different based on the capacity and power of their engines. Still, normally, the power of air ejection and effective heating in the space in front of each unit heater can be considered from 8 to 20 meters.

If you use a steam unit heater, pay attention to the important point that the amount of heating in the steam unit heater is directly related to the steam pressure entering the heating coil of the unit heater.

In other words, if the inlet steam pressure is equal to 5 psi, the heating value of the same unit heater is much lower than when the inlet steam pressure is 15 psi. Therefore, when choosing a steam unit heater, pay attention to the available steam pressure to provide heat energy.

Using Unit Heaters for Cooling

Can a unit heater be used to provide cooling as well?

As is well known, a unit heater is a heating device designed to distribute warm air in industrial, commercial, and sports facilities. Its primary function is based on utilizing hot water or steam generated in a central boiler room to quickly deliver the required heating to large spaces. However, in certain industrial projects, unit heaters can also be employed for cooling purposes.

One common method of using a unit heater for cooling is by installing an additional cooling coil or adding an extra coil row to the conventional two-row hot water or steam heating coil used in unit heaters. In this configuration, the unit heater fan forces air to pass over the chilled water coil, resulting in a relative reduction in ambient temperature. This approach is suitable for spaces with limited cooling demand or as a supplementary solution alongside a central cooling system, but it cannot replace fan coil units or air handling units.

For optimal performance of a unit heater used for cooling, several factors should be considered:

• The cooling coil capacity must be properly matched to the volume of the conditioned space.
• The fan air velocity and airflow rate should be adjusted to achieve efficient cooling heat transfer.
• Installation of a drain pan beneath the chilled water coil of the unit heater is essential.
• Using unit heaters for cooling is best considered with the main cooling system as an auxiliary solution.

In conclusion, a unit heater can function as a supplementary cooling system in industrial halls. The use of unit heaters for cooling is mainly recommended in industrial and commercial projects equipped with a central chiller system and where cooling requirements are relatively limited.

Factors to Keep in Mind when Installing a Unit Heater

The following factors will help you install your unit heater correctly:

• Installation of unit heaters is usually done based on the dimensions and weight of each unit heater on a frame made of a corner or steel shield of size 3 to 5, and the suitable installation height for wall unit heaters is at a height of 2.5 to 3.5 meters from the floor level. Environment (based on the capacity of the unit heater and the height of the installation location).
• In the hot water unit heater, the hot water inlet pipe is connected to the bottom of the device, and in the steam unit heater, the steam inlet pipe is connected to the top of the steam unit heater.
• The hot water and steam coils of the unit heater may be one or two rows, but please note that before ordering the unit heater needed for the project, you must declare whether the inlet and outlet pipe of your unit heater is on the left or right.
• It is necessary to install an automatic air valve in the return water path from the hot water unit heater.
• It is also necessary to install the barrel nut and valve on the pipes connected to the inlet and outlet pipes of each unit heater.

Calculation of the water flow rate in the circulator pump of the hot water unit heater:

If you need to calculate the flow of hot water, divide the capacity of the unit heater (BTU) by 10,000 to get the amount of G.P.M of hot water circulating in the unit heater. If you require more advice, you can contact the experts of DamaTajhiz HVAC.

How to Choose a Unit Heater

Before choosing the heating capacity and motor power of the required unit heaters, you must first determine the type of heating fluid available (hot water or steam) and how the unit heater will be placed (wall or ceiling).

In some cases, specifically for climates that have moderate summer temperatures and also have a central cooling system (chiller), unit heaters can be used to provide cooling in summer.

In this situation, in addition to the existing and standard two-row coil, another coil must be added as an option for cooling, as well as the corresponding drain tray under the cooling coil of the unit heater.

Buying a Unit Heater

To select and buy a suitable hot water or steam unit heater, you must first determine the type, capacity, and brand of the unit heater.

Here at the DamaTajhiz HVAC store, the technical information of dozens of models of unit heaters from reliable brands with warranties has been presented in order for you, dear ones, to enjoy the good feeling of an optimal and smart purchase.

Also note that in the specialized HVAC group of Damatajhiz, all the unit heaters are only sold in bulk. Therefore, if you want to wholesale any of these products, feel free to contact us.

The Price of Unit Heaters

Choose and buy all types of unit heaters at the best price on the website of the specialized DamaTajhiz HVAC.

The price of unit heaters varies according to the variety of models and brands available; it should be noted that the prices presented in the heating equipment collection are updated, and the discounts desired by consumers are included in these prices for wholesale purchases.

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Dear Users;

While thanking you for your trust in the technical opinions of the sales experts of DamaTajhiz HVAC Group, it should be mentioned that the determination and selection of the desired product brand based on history, brand strength, service, and product price is ultimately determined by the buyer.

But in Unit Heater, most of the users and buyers purchase best-selling brands such as DamaTajhiz and Saran according to their quality, price, and after-sales service.

You can order any HVAC and MEP products, including different types of air washers, cooling towers, air handling units, chillers, industrial evaporative coolers, air curtains, burners, cast-iron or steel boilers, heat exchangers, gas heaters, unit heaters, circulation pumps, sand filters, water and fuel storage tanks, and more, from countries such as the UAE, Armenia, Tajikistan, Georgia, Azerbaijan, Turkey, Oman, Pakistan, Turkmenistan, Afghanistan, Kuwait, Bahrain, Qatar, Iraq, and others across Asia, the Middle East, and Europe, and have them delivered to your city (Manama, Baghdad, Karachi, Dubai, Sharjah, Muscat, Riyadh, Abu Dhabi, Kuwait City, Jeddah, Sana'a, and Doha Amman, Sulaimaniyah, Sofia, Kirkuk, Islamabad, Mosul, Erbil, Dushanbe, Aleppo, Damascus, Baku, Beirut, and Kabul) in the shortest possible time. So, contact us by phone call or WhatsApp message through the number: +98-930-288-0251.

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