Keys to efficient dehumidification michaels energy. Applications, such as computer rooms, textile mills, and furniture manufacturing plants require that a constant relative humidity be maintained at. Most software assumes the btuh load is the coil load. Heater selection and sizing formulas for bel thermal units, inc. This site uses cookies to offer you a better browsing experience. Open coil electric duct heater marley engineered products. Incorporation of an airflow sensor allows the sdv to compensate instantly for any change in supply air pressure that might alter the supply volume resulting in a pressure independent variable air volume system. Variable by volume varitrane single duct vav trane.
Typical hvac rules of thumb abraxas energy consulting. A small pump circulates the working fluid usually a solution of inhibited glycol and water through the two coils. Interlocking panel design provides the most rugged vav unit available. Heating and cooling coils, water coils, refrigerant coils, steam coils, heat recovery, electric heater batteries, replacement coils, coil selection software. Applications are evaluated using the latest windowsbased performance and sizing software, which accommodates nearly any heat transfer medium. Their primary function is to regulate airflow to a zone, in response to zone temperature requirements. Price electric coils are factory mounted, etl listed to meet electrical safety standards, and comply with dual designation csa 236ul 1995. System the user indicates to the program to save the cooling coil air. Coil calcs certified ratings are application ratings resulting from our tests according to standard test codes in agreement with ahri standard rating methods for standard 410. The program now includes enhanced features to aid customers selecting replacement hvac coils. The program was officially shut down december 31, 2017. Masduct commercial services ltd recommended for you.
Coil loop for exhaustair energy recovery a coil loopalso called a coil runaround loopconsists of two or more finnedtube coils that are piped together in a closed loop. Use the coil selection software for quick, efficient parameter specification to receive the exact replacement needed. In the real world of valve sizing, this will almost never be known. Standalone coils supplied as duct heaters are certified in compliance with ul 1996. Hvac coils custombuilt replacement coils restore comfort and prevent damage. By continuing to navigate through this site or by clicking approve, you consent to the use of cookies on.
It is not covered by the marley engineered products merchandise return policy and is noncancellable, exchangeable, or returnable. By continuing to navigate through this site or by clicking approve, you consent to the use of cookies on your device as described in our privacy notice. Furthermore, labs are a little more complicated than offices, because they typically have room. Electric heaters are purely resistive loads, amperage will decline with applied voltage. Simple calculations determine the proper size heating coil and can help solve a heattransfer problem. They are only typical values, which should be verified for each application. Hap calculates required space, zone and system airflow rates. Berg, mechanical engineer, colmac coil manufacturing, inc. Designed for cooling only, cooling with reheat, heating only or heatcool changeover applications. This field is ignored for gas or electric reheat coils. Electric heat the electric heater provided with most single duct vav boxes is essentially a rated duct heater installed in an elongated single duct unit.
If dp across the valve is unknown, use 50% of available inlet pressure. Dehumidification and reheat dehumidification lowers the drybulb temperature, which often requires the use of reheat to provide comfortable conditions. In this enl program, trane engineers will discuss the application, selection, and optimization of both chilledwater and hotwater coils. Electric reheat coils are an available accessory for use with price single duct and fan powered terminal units.
These units are generally applied in coolingonly vav zones that require no heat during occupied hours. Sizing heating and cooling coils products finishing. The unit is designed to allow maximum flexibility in configuration and control. Carrier hap hourly analysis program softwares hvacr. Air going through a typical cooling coil is not only sensibly cooled, latent cooling is also involved although sensible cooling normally accounts for the majority of the cooling. Quiet type with dissipative silencers and hospital grade boxes are also available.
In tanks with currentcarrying racks, accidental contact between a rack and coil may cause an electrical arc, resulting in a hole in the coil. Select a one or two row coil for the desired gpm and mbh requirements from the graphs for the unit size and the cfm required. This situation is exacerbated in laboratories due to the wide range in internal loads figure 1. The air flow rate used for reheat coil sizing is reported with other component sizing information as reheat coil sizing air volume flow rate. Autosizing procedure assumes that electrical heating element in the. Keys to efficient dehumidification page 4 reheat dehumidification via mechanical cooling occurs by driving the conditioned air temperature down to the desired dew point.
I was attempting to use cv with terminal reheat but not seeing the light. Due to compatibility issues with ms silverlight we had to abruptly pull our selection software program from general use. Complete air control and distribution solutions nailor. How is the heating coil selection information calculated. Dehumidification and reheat are actually two processes on the psychrometric chart. The above equations for air do not apply to the majority of cooling coils the equations for water apply to both heating and cooling coils. In this section you will find all tech time articles related to electric duct. Finned tube and open coil styles are available and can be custom designed up to kw. Rahn industries manufactures a full range of fin and tube heat exchangers including chilled and hot water coils, glycol coils, booster reheat coils, evaporator coils, condenser, steam and other exact fit oe, custom and severe duty coils that are guaranteed to fit and perform. This longer unit provides for developed flow, after the damper, and a.
With this software, your local indeeco representative becomes the source for certified prints, wiring diagrams. There are several equations that can be used in conjunction withthe colmac coilpro selection softwareprogram to speed the process of sizing coils. Performance selection data hot water heating coils non. In one case, the software correctly activated the reheat coil when the vav box damper reached its minimum stop and the zone temperature was still below the. When too much air at the desired dew point temperature is supplied to a space, the air must be reheated to maintain desired conditions. First, the program performs a psychrometric and analysis to determine. The 35e single duct unit provides cooling only or cooling with reheat to meet most application requirements. Heating elements shall be open coil type, 80% nickel 20% chromium. Use the coil selection software for quick, efficient parameter specification to. Select air coolers based on design requirements and let the software pick the unit that meets your most important criteria price, size, efficiency, etc. Performance selection data hot water heating coils. The reheat coil acts as a shim, a backup in case the designers load estimate isnt exact. Nailor 3000 and 3100 series terminal units are among the most versatile vav boxes on the market, providing easy hvac system integration with diverse control packages. Also, if youre interested in learning even more, heres a free download for you.
The baseboard is suppose to take care of the envelope loads and the vav electric reheat coils will take care of the rest. If neither the dp across the coil or the valve is known, use 5 psig as the minimum dp. The small size of the unit ensures an easy fit in most applications. The program will use the sizing inputs to size the coil.
Under certain climatic conditions and when the amount of return air is consistently high, computed cooling coil enteringair temperature can be a valuable guide. Ideally, its always best to extend existing ductwork from your central furnaceair conditioning system, but sometimes its just not possible to route additional ductwork. Source removal during a commercial duct cleaning project in surrey mas duct duration. Designed, manufactured and tested to meet a broad range of heating and cooling. Refer to the electric coil selection procedure below for. Sizing data is provided for central cooling and heating coils, preheat and precool coils, fans, humidifiers, terminal reheat coils, cav and vav air terminals, fan powered mixing boxes, perimeter baseboard units, fan coils and terminal heat pumps plus chillers and boilers. Coils are available for the oem channel in a wide range of custom sizes and material options. Aerofin products serve a variety of industries including hvac, fossil fuel power generation, nuclear power generation, industrial process, pulp and paper, automotive, and petrochemical. If the dp across the coil is known, the valve dp should be the same. At commercial coils, we provide exceptional service to customers around the world in the heat transfer industry. What better way to learn energy modeling software than screen. We offer all types of coils for heating, cooling, refrigeration, hvac, and laundrydry cleaning equipment. The electric heating coil is a simple capacity model with a userinputted efficiency. This longer unit provides for developed flow, after the.
Coil data is based on 125 51c temperature difference between entering air and entering water. This air may be tempered with a reheat coil, plenum air, or both. Vavbox selection, code conformance hpac engineering. If local zone heat is necessary it can be provided either remotely for example, perimeter heat or by terminal reheat either electric or hot water coils. The quick build program builds and ships replacement coils, turning around orders in one to 25 days to meet your requirements.
Heatcraft coils are ahri certified because we have confidence in what we build. Our electric duct heaters provide enhanced comfort by maintaining or accelerating warm air flowing throughout ductwork within a building, especially in areas furthest away from the main hvac unit. Can somebody give me a good explanation why typically when you size heating coils in vav systems either reheat coils for vav boxes or in the vav ahu is it customary to size the coil for about 50% of the maximum cooling airflow rate. Hvac valve sizing in the real world industrial controls. Electric heat the electric heater provided with krueger lmhs series single duct vav box is essentially a rated duct heater installed in an elongated single duct unit. Knowing the heating load of the space btuh or mbh, room temp setpoint, and the air flow rate during heating based on minimum ventila. The software is called the trane official product selection system topss. Single duct terminals are the fundamental building blocks for variable air volume vav systems. Installing electric baseboard heating is often the easiest and most effective way to add heating to a room addition or when you are converting an unheated space, such as an attic or basement. All duct heaters shall be tested and certified to ul std 1996 ul file number e245517. With minimal pressure drop and low noise levels the sdv controls the airflow rate of conditioned air into an occupied space in response to a thermostat control signal. Recommended specifications electric duct heaters recommended specifications provide open coil electric duct heaters of the size, capacity and performance shown on the job schedule.