What data should be sent before inquiring about heat exchangers? Thermal, Mechanical, Materials...
Many purchasing personnel think that "quotation information" means model, quantity and target price. For heat exchangers, this is not enough. The essence of the heat exchanger quotation is that the supplier uses the data you provide to establish an engineering hypothesis: how the medium flows, how the heat is transferred, whether the material is suitable, whether the equipment can withstand pressure, whether it can be installed on site, and whether it can be maintained in the future. The more complete the data, the closer the quotation is to the true purchase cost; the fuzzier the data, the easier it is for the quotation to become an incomparable estimate.
If you are going to inquire from Chinese suppliers, you can first divide the data into five categories: thermal data, mechanical data, material and corrosion data, operation and maintenance data, and commercial and delivery data. Quick Inquiry Form has broken down these contents into basic information, product type, quantity, delivery date, additional instructions and attachments to upload; if the project is complex, it is recommended to upload Excel or PDF datasheet.
1. Thermal data: determine equipment size and heat exchange capacity
Thermal data is the first layer of the quote. Suppliers need to know at least the hot and cold media, flow rate, inlet and outlet temperatures, pressure, phase state and allowable pressure drop. For many projects, flow rate and temperature are more important than "heat exchange area", because the area is only the calculation result, not the working condition itself. TEMA's open standards page mentions that its specification sheet updates are used to better define heat exchanger design requirements; this is consistent with actual procurement experience: suppliers need calculable inputs, not fuzzy results.
| Data items | Example writing | Remarks |
|---|---|---|
| Hot side medium | Hot water, thermal oil, steam, process gas | If it is a mixture, the main components should be written |
| Cold side media | Cooling water, seawater, glycol, air | Special instructions recommended for seawater and chlorinated water |
| Flow | 120 m3/h or 100000 kg/h | SD mass flow or volume flow |
| Temperature | 95°C to 65°C; cold side 30°C to 45°C | If only the heat load is known, also state |
| Pressure | Operating pressure, design pressure, test pressure | Pressure vessel standards will be affected |
| Pressure drop | Maximum allowed kPa per side | Depends on pump power, number of channels and number of tube passes |
2. Mechanical data: determine whether the equipment can be manufactured and accepted
Mechanical data includes design standards, flange standards, nozzle size, installation orientation, pressure vessel certification, non-destructive testing, hydraulic testing, painting, insulation and packaging. The public description of ASME BPVC Section VIII Division 1 shows that its scope covers the design, manufacture, inspection, testing and certification of pressure vessels with internal or external pressures exceeding 15 psig. The purchaser is not required to write the full standard clause in the initial inquiry, but it is recommended to clearly state whether the project requires ASME U Stamp, PED, GB, project specifications or third-party witnessing.
For shell-and-tube heat exchangers, the mechanical data is often heavier than that of plate-type equipment, because the tube sheet, shell, tube bundle, expansion joint, support, and maintenance and core pulling space must be considered in advance. For TP welded plate heat exchanger, the welded structure, pressure level and cleaning method are the focus of the quotation.
3. Material and corrosion data: determine the part with the biggest difference in quotation
Quotations from different suppliers vary greatly. In many cases, it is not the profits that are different, but the material assumptions. The cost and applicable boundaries of 304, 316L, titanium, duplex steel, Hastelloy, copper-nickel alloy, carbon steel lining, rubber pad, EPDM, NBR, FKM are all different. The purchaser can provide information such as chloride ions, pH, sulfide, particles, viscosity, contaminants, cleaning agents, CIP temperature, whether it is food grade or pharmaceutical grade.
| Media risk | Description required | Possible impact |
|---|---|---|
| Seawater or brine | Chloride ions, temperature, flow rate, stagnation | Materials, corrosion margin, filter |
| Oil or organic solvent | Flash point, viscosity, impurities, pressure | Sealing, welded structure, explosion-proof |
| Food or pharmaceutical | Cleaning agents, hygiene requirements, dead space restrictions | Material polishing and cleanability |
| Slurry or fiber | Solid content, particle size, viscosity | Wide channel or tubular solution |
| Steam condensation | Steam pressure, condensate discharge | Hydrophobic and water hammer risks |
4. Operation and maintenance data: determining life cycle costs
DOE information on cooling tower side filtration points out that dirt and scale will form an insulating film on the heat exchange surface and increase the energy consumption required to remove heat from the chiller; side filtration can reduce suspended solids and microbial-related problems, but it cannot replace chemical water treatment. This idea applies to most heat exchanger purchases: in addition to the price of the equipment, it also depends on subsequent cleaning cycles, pressure drop rise, spare parts and downtime costs.
The purchaser can indicate whether existing equipment is frequently fouled, whether online cleaning is required, whether disassembly is allowed, spare parts inventory strategy, expected operating cycles, downtime windows and maintenance personnel capabilities. For removable plate heat exchanger, the maintenance focus is on the plates, gaskets and compression dimensions; for Wide gap welded plate heat exchanger, the focus is whether it is truly suitable for media containing particles, fibers or high viscosity.
5. Commercial and delivery data: determine whether the supplier is willing to make a serious quotation
Suppliers will also judge the quality of inquiries. A clear inquiry document will usually describe the project location, target delivery date, purchase quantity, whether quotation validity is required, whether spare parts are required, payment method, target certification, end-user industry, language document requirements and whether alternatives are allowed. Many Chinese suppliers will first give a very rough price when facing inquiries with vague information; if the information is complete, the suppliers are more willing to invest engineers to do thermal calculations.
6. Recommended data sending sequence
The first step is to submit the minimum quotable data: medium, flow rate, temperature, pressure, quantity, application industry and target delivery date. The second step is to supplement the boundary information: materials, corrosion, pressure drop, flange, installation space, standards and certifications. The third step is to upload attachments: drawings, old nameplates, photos, datasheet, P&ID, and project specifications. The fourth step requires the supplier to return a thermal work summary, material description, weight and dimensions, delivery document list and deviation table.
You can use Inquiry Form as the first step to submit the project description and attachments together; you can also browse Manufacturers List and Product Catalog to determine the general product direction before making an inquiry. The point is not to fill everything in at once, but to let the supplier know which data is certain and which requires them to ask questions.
8. If the parameters are incomplete, how should they be written?
Many real projects do not have complete parameters in the early stages of inquiry, which is normal. The key is not to fill in every box of the form, but to distinguish between known information and unknown information. For example, if the hot side only knows the medium and inlet temperature, but not the outlet temperature, it can specify whether the target is cooling, heating, waste heat recovery or condensation, and ask the supplier to back-develop the boundary conditions that need to be supplemented. Another example is that the cold side only knows the source of cooling water but not the actual flow rate. It can provide on-site pump capacity, pipe diameter or allowable pressure drop range, allowing the supplier to determine whether conservative design is needed.
If you have no thermal data at all and only know that "old equipment needs to be replaced", the most valuable information is the old equipment nameplate, appearance photos, interface locations, site space, failure causes and past operating problems. Frequent scaling, leakage, excessive pressure drop or difficulty in cleaning of old equipment are themselves signals for selection. The supplier may recommend continuing to use the same type of equipment, or may recommend changing from a gasketed plate type to a wide-channel welded plate type, from a plate type to a shell and tube type, or to retain the shell and tube type but adjust the materials and structure. The purchaser can ask the supplier to explain the reasons for changing the selection instead of just giving one model.
9. Attachments can reduce errors better than text
In inquiries, attachments are often more useful than long descriptions. It is recommended to prepare at least some of the following materials: process datasheet, P&ID, on-site photos, old equipment nameplate, installation space sketch, interface orientation diagram, project specifications, material requirements, third-party inspection requirements, packaging and transportation requirements. Inquiry form already supports uploading common files such as images, PDF, Word, Excel and CSV, which is suitable for submitting scattered information together.
But the attachments should also be explained. By uploading just one PDF without explaining the priority, the vendor may not know which version takes precedence. A better way to write it is: first, explain the goal of this inquiry; second, list the name and purpose of the attachment; third, indicate which parameters can be suggested by the supplier; fourth, require the supplier to list assumptions in the quotation. In this way, even if the parameters are temporarily incomplete, a traceable technical communication record can be formed.
Data sources and site links
- TEMA Standards and specification sheets: https://tema.org/standards/
- TEMA Heat Exchanger Specification Sheet: https://support.tema.org/images/TEMA_USC_DataSheet.pdf
- ASME BPVC Section VIII Division 1: https://www.asme.org/codes-standards/find-codes-standards/bpvc-viii-1-bpvc-section-viii-rules-construction-pressure-vessels-division-1
- DOE Cooling Tower Side Filtration and Fouling Instructions: https://www.energy.gov/cmei/femp/water-efficient-technology-opportunity-side-stream-filtration-cooling-towers
- Shell and tube heat exchanger: https://heatexdirect.com/products/siping-viex-heat-exchange-equipment-co-ltd/tubular-heat-exchanger
- TP welded plate heat exchanger: https://heatexdirect.com/products/shanghai-heat-transfer-equipment-co-ltd/tp-welded-plate-heat-exchanger
- Removable plate heat exchanger: https://heatexdirect.com/products/shanghai-heat-transfer-equipment-co-ltd/gasketed-plate-heat-exchanger
- Wide gap welded plate heat exchanger: https://heatexdirect.com/products/shanghai-heat-transfer-equipment-co-ltd/wide-gap-welded-plate-heat-exchanger