Selection and Purchase of Hot Water/Steam Unit Heater
Unit heaters are used to provide heating for halls such as workshops, large stores, and projects that have a central hot water or steam engine room. In the following, information, technical specifications, capacity estimation, and the best purchase price for hot water and steam unit heaters have been provided for wholesale purchase. So don’t miss out.
Guide to Review, Select & Buy Hot Water/Steam Unit Heaters
Unit heaters receive the hot water or steam needed by their heating coils from the central engine room of the building. Unit heater is a device that can heat large spaces such as sports halls, factories, and companies in the shortest time.
Approximate Estimation of Hot Water/Steam Unit Heater Capacity
To calculate the approximate heating requirements of the halls or to use unit heaters based on the temperature conditions of the geographical region (air temperature outside in the winter), dimensions and type of use of the hall space (temperature inside), the type of materials used in the construction of the hall, etc. You can consider the heating capacity of about 250 to 400 btu/hr per cubic meter of air volume in the hall, according to the opinion of facility experts.
The above capacity estimate is approximate, and for warm and temperate cities such as Tehran, Isfahan, Shiraz, Mashhad, Rasht, Semnan, Mazar-e-Sharif, Kabul, Erbil, Mosul, Aleppo, Damascus, Kirkuk, etc., this number can usually be determined by the opinion of the facility expert. About 250 to 300 BTU per cubic meter of the hall space and for cities located in winter and colder climates such as Zanjan, Tabriz, Ardabil, Urmia, Sanandaj, Sulaymaniyah, Baneh, Samarkand, Khojand, Eshgabat, Dushanbe, Baku, Yerevan, Ankara, etc., the required heating is about 300 to 500 BTU per cubic meter of the volume of the hall. It should be considered based on the calculations of experts.
The formula for calculating the heating capacity of Unit Heaters
The following is the formula you need to calculate the thermal capacity of a hot water/steam unit heater:
QT heating load of each unit in kilocalories per hour
U1 to Un heat transfer coefficient of each surface between the inside and outside of 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 is the temperature difference between the inside and outside of 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 English units
In this formula, by calculating the values of all the above parameters, you can get accurate results to determine the heating capacity and the number of unit heaters required for the hall. Note that the exact values of U and area A for each of the surrounding surfaces must be considered based on specific details in each building and engineering tables of the heat transfer coefficient.
Types of Hot Water/Steam Unit Heaters
Unit heaters are divided into several for providing ambient heating in terms of fluid type, installation location, air flow direction, and application.
In terms of installation, unit heaters are divided into two categories: ceiling unit heaters and wall unit heaters.
In terms of the type of fluid, the unit heater is divided into two categories: steam and hot water.
The outlet air in the unit heater can be horizontally and vertically or in any desired direction.
Advantages and Features 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 hall environment
High speed in heating the environment
The ability to install and throw air horizontally and vertically
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).
Due to the noisy operation of the unit heater fan at 1400 rpm, it is better to order the unit heater with a two-speed or 900-speed motor (but with a higher heating capacity).
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.
Unit Heater Components and Parts
Unit heaters usually consist of five main parts:
The Body: The cubic body of the device is usually made of steel sheets.
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.
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.
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.
The Vanes: The vanes are installed in front of the unit heater and are able to direct the hot air coming out of the unit heater.
Hot Water/Steam Unit Heater Performance
In hot water unit heaters, the required hot water flow from the engine room to the coil of each unit heater is provided by the circulator pumps installed in the project engine room, with the calculated flow rate and head (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 hall 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.
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. Hall (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 circulation of the circulator pump of the hot water unit heater:
If you need to calculate the flow of hot water, divide the capacity of the hot water unit heater (BTU) by 10,000 to get the amount of G.P.M of hot water circulating in the unit heater. If you need more advice, you can contact the experts of DamaTajhiz HVAC.
Buying Hot Water and Steam Unit Heaters
In order to choose and buy a suitable hot water or steam unit heater, you must first determine the type, capacity, and brand of the unit heater. On the site of DamaTajhiz HVAC, the technical information of dozens of models of unit heaters from reliable brands with warranty 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 Hot Water and Steam Unit Heaters
Choose and review 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 purchase. So that these prices also include the part guaranteeing the best prices on the DamaTajhiz HVAC
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.
If, after reading the above pieces of information, you still have questions about the decision to purchase the type of unit heaters you need, you can get advice from the sales experts of the Heating Equipment and Machine Room Department by contacting the DamaTajhiz HVAC Group and calling extension numbers 107-108-121-122. And ask your questions.
"Purchase with confidence and peace of mind from DamaTajhiz HVAC Group."
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