We spoke about it in the past.
These requests coming sometimes from pharma research & development department and involving small thermal capacity units.
Made these units seems simply.
Anyway technical department, when drawing this machinery, take in account many features to avoid problems which can results when plant starts.
Heat exchangers, regulation valve, pump and many other component need more attention then other.
If heat exchangers or regulating valves are too small, you cant get the duty, but if they are too large, you cant achieve the perfect temperature control request from process.
Sometimes out engineering department need to apply “tricks” to achieve the correct result which customer ask to us.