My ultimate "wish list" as a design engineer would be to have access to the design programs for all of the new and innovative products in the industry. Often the new technologies are "black box", as we request the designs from the proprietary manufacturer, we are not given access to how those designs are rated. When it comes down to comparing competitive manufacture designs, say for welded plate exchangers, we as the engineering company have to take the vendor's word for if the exchanger will perform as designed. The most innovative technologies require a leap of faith in respect to both the engineering company and ultimately the client who is purchasing the technology
1. For air compressor inter stage and after coolers the auto condensate drain system should work perfectly. My experience is very discouraging on this aspect. 2. Tube bundle should be easy to handle with special arrangements if needed. 3. Special coating for water boxes for corrosion prevention.
A)Product which can take care of external impurities in the cooling medium. b)Unit which can be easily serviceable. In fact this is one of the important points on which the selection lies. The shell and tube configuration scores over plate heat exchanger in spite of compactness and efficiency of PHE
Thermal design, mechanical calculation for shell & tube heat exchanger, pressure vessel & columns, expertise in designing of typical type of exchanger for highly corrosion & chemical resistant material (tantalum, titanium, zirconium, niobium etc.)
Heat exchangers are very vital in any oil and gas down stream business. To this extent, we need to avoid rogue materials that would lead to failures. This means that we need hex designed with the best materials that can guarantee reliability.
Clean water, my applicable heating element could easily do this with small solar application with rechargeable batteries for 24/7 use. Heating air same and easier with even lower energy consumption but clean water is badly needed.
Needs to be easily maintainable. Support for the chemistry side of things is also important. Small footprint is desirable. Gaging should be easy access and easy to read. Back-up systems are essential.
1. A good visible heat exchanger for the research purpose 2. A new design of heat exchanger controlled digitally so we can study and know every thing inside.
1. Brazed titanium HX for refrigerant application. 2. Brazed high corrosive resistant stainless steel HX for use with refrigerant against LiCl solution.
Advanced materials, with good thermal and corrosion performance. Internal flow designs to minimise pressure loss, while maintaining thermal performance
Industry standards for interchangeable units (capacity, size, inputs); new materials for lighter and more efficient exchangers; lower cost;
More consistent use of metals to do away with anodes. Too many systems have bronze stainless 316 , 2205 steel and various other metals
Heat Exchangers for super critical service of pressure and temperatures as encounters in super critical thermal power plants.
Easy dis-assembly, re-assembly for plate and frame HX's. Use of enhanced surfaces for inner tubes of fin-tube style HX's.
Manufacturers listed by capacity (small, medium, big ones) materials of construction (c.s., s.s., alloys)
Rugged and versatile, Ease of Maintenance, Cost of Exchanger, Overall Heat Integration
Be sure that you include provisions for adequate instrumentation...Pressure gauges, thermometers, and flow meters. Also include provisions for Clean In Place so that the heat exchanger can be cleaned early in the fouling stages. Do not specify "clip on" style gaskets unless it is an application that requires frequent changing of the gaskets. In typical non corrosive applications, glued on style are much more user friendly when opening to service the equipment.
Look at the exchanger with the entire system in mind. If you only design the exchanger from the required duty, flow rate, allowable pressure drop, you might miss an opportunity to possibly reduce the amount of exchangers required for your overall process. Sometimes if you can have a higher allowable pressure drop, you can make the design more efficient with higher shellside/tubeside velocities which also can discourage fouling.
Highest flow your budget allows - up to 10% higher than what you think you need. So you don't have to do a Scotti and say, "She's giving it all she's got captain!"
Verify systems design carefully avoiding water hammering which is destroying piping, valves and equipment, including heat exchangers. The VFD motor driven pumps and throttle valves shall be used preventing water hammering.
Ensure that differential thermal expansion can be accommodated without exceeding the stress concentrated fatigue limit. Do not ignore condensation film coefficient. It can add a surprising resistance to heat transfer.
Avoid cycling too much the temperature inside a flat plate heat exchanger (leaks occur in few years). In this case, it would be better to use a Shell & Tubes, whatever the flat plate heat exchanger suppliers say.
Hexs may fail in service if wrong choice was made on day one. Ensure that process parameters are observed from time to time. Carry out regular maintenance inspection in keeping with statutory requirement.
What type <-> what application. First issue is to decide heat exchanger type. Most likely the best solution comes from company who has several types and are not "binded" for certain type...
When replacing "like for like" ensure that this is really what you're doing - even relatively (seemingly) small changes can make an effect especially in thermosyphon reboilers.
Do not use heat exchangers as band aids. An engineered solution making the system more efficient will often eliminate the need for or reduce the size of the heat exchanger.
Get one that is sized for worst case scenarios. You do not want an exchanger that is too small when the worst of weather conditions effect your building systems.
1. Use close control temperature sensors. 2. Always use differential pressure sensors across PHE. 3. Use good strainers.
Use Qualified Service personnel that are used to doing work on them - Each type and manufacturer has their little quirks.
If using a heat exchanger to cool liquids below freezing, be sure to install freeze up protection, and flow valve safeties.
Many manufacturers do not give data sheets at bidding stage; they give just a brief description, problems come later...
1. Back flooding of Reboilers. 2. Vibration in U-Bends. 3. Tube end erosion due to excessive rho v sq.
Keep good relation with technicians in the field who offer advice, as the "old guys" are a valuable resource.
Make sure to consider all the components on a fluid to select the correct construction materials.
Make sure there is advanced computer analysis of a proposal to back up your selection.
Avoid pumping loss due to inefficient flow path. Select corrosion resistant materials.
Double check performance by obtaining several quotes. Beware of underperformance.
Pay attention on operation temperatures, flow and pressure.
Not change the design parameter to the moment to use it.
Before selecting, take advice from HVAC consultant.
Proper maintenance for your heat exchanger.
Be careful with dust and filter using.
Speak with reliable manufacturers.