Electric Heat Exchangers
4Pages

HEAT EXCHANGERS Application: Heating of Forced Convection Fluids Figure 1: Typical Sketch of an electrical heat exchanger GENERAL CHARACTERISTICS TECHNICAL DATA Heat Exchangers are the best solution to heat fluids flowing in forced convection. Electrical Heat Exchangers operate in the same way as fluid/fluid heat exchanger but the hot side consists of armoured electrical heaters in direct contact with the fluid to be heated. An optimum heat exchange is obtained employing appropriate baffles whose design is tailored to exploit at best the heat released by the electrical resistances. Heat Exchanger can be manufactured with carbon steel or stainless steel shell: 1 2 3 4 5-6 Power supply cable inlet Eyelets for heat exchanger hoisting or moving Supporting frames for mechanical fixation Thermal insulation (if requested) Drain connections Thanks to the specific characteristics of the heaters, the Electrical Heat Exchangers are very compact in size and support a very precise control of the fluid outlet temperature. These systems, in fact, are characterised by a minimum thermal inertia of the hot side of the exchanger, thus providing a very fast response to the process needs and a finely controlled outlet temperature. This is especially true if SCR’ (Solid Control Relais) are employed in the s control system. These products are designed by our technical department on the basis of customer provided functional requirements. Design is supported by purpose-developed software that allow both the definition of the design parameters and the verification of the corresponding thermodynamic performances. The analysis yields a precise picture of the heat exchanger operating conditions. The iteration between design and analysis lead to define: Fluid Electric Heaters If requested by customer specifications, mechanical verification calculations, for the structurally significant parts (coupling flanges and shell), are provided in the frame of the order. They fulfil the requirements of European (PED 97/23/EC), American (ASME VIII div.1) and are executed following national (VSR, AD2000, etc.) standards. 1. the specific power 2. the requested number and type of baffles as well as the resulting pressure drops 3. the maximum sheath temperature and, consequently, the safety devices to be used 4. the materials to be used in the construction 5. The heat exchanger main dimensions 6. the thermodynamic behaviour of the heat exchanger in the different operational conditions that are foreseen The manufacturing experience built up in several years of operation in the market, copying with the most different applications, enables us to suggest to our customers materials and technical solutions which are best suited to the application of interest. The results of the thermodynamic calculations, performed to prove the capability of the heat exchanger to operate as requested, are provided already as part of the offer.

HEAT EXCHANGERS Application: Heating of Forced Convection Fluids DEFINITION OF THE TYPE OF HEATING Ä Heating of moulds or blocks containing fluidcirculating loops Ä Oil separation and filtration Ä Combustible oils pre-heating Ä hot transfer of heavy oils Ä Hot water supply to cleaning and rinsing tanks Ä Anti-frost protection Ä Technical and process gases heating Ä Additional heating unit (back-up of the primary one) The sizing of a heat exchanger changes significantly if the requested heating shall be obtained in a single passage of the fluid (“ single passage” heating) or if, on the...

HEAT EXCHANGERS Application: Heating of Forced Convection Fluids DATA REQUIRED FOR A CORRECT DEFINITION OF A HEAT EXCHANGER To design the heat exchanger a set of data is required. The availability of all the data is a pre-requisite for an optimum sizing and for a precise definition of the heating power. The Table 1 presented hereunder summarises the required data. Table 1: data required to design an electrical heat exchanger Design Data Thermodynamic Data ð For non common fluids please specify the thermodynamic characteristics at, at least, three different temperatures thermodynamic...

Applicazione : riscaldamento fluidi in convezione forzata Additional information are required if optional components (thermal insulation or cable glands) are to be supplied with the heat exchanger or if the heat exchanger design shall comply with the requirements of specific standards. The data in Table 1, in this case, must be completed with those listed in Table 2. Table 2: design data to be provided in case optional components or specific certifications are required Thermal Insulation Masterwatt Standard as a function of the operating temperature Please specify: material and Φ external...