2 Pipe Fan Coil System Issue and Solutions

[2-Pipe FCU]

Want to learn the effective solution for solving the Hotel's 2-pipe fan coil system issue.

The hotel has a 2-pipe system (chiller/boiler) that currently uses fan coils.
It is a historic building. The hotel's operation is quite good, but it is receiving quite some heating or cooling complaints from the hotel guests.

The 2-pipe fan coil works on cooling or heating within the whole building at any given time.

The requirement:
*The hotel wants to be able to cool/heat all year round while keeping the existing HVAC and piping system.
*The hotel doesn't want to do major construction and doesn't want to pause the hotel's operations.

Any good solution? Thank you.

 

[HVAC-Novice]

In 2-pipe the entire hotel will either heat or cool (at least the entire system, in case it has multiple systems). As you noted, this creates issue since you often have simultaneous heating and cooling load. What you need is a 4-pipe system or other system that inherently can heat and cool at the same time. Or have a separate heating system (like hydronic radiators) and the FCU only for cooling.
A lot depends on the climate. if climate is very mild, electric heat could be an option.

Your username basically will prevent you from asking any questions about other HVAC topics

 

[MintJulep]

The hotel doesn't want to do major construction and doesn't want to pause the hotel's operations.

If you're constrained to doing nothing then there's nothing that you can do.

Perhaps the lowest impact would be replacing the FCUs with water-source heat pumps.

 

[2-Pipe FCU]

Thank you, HVAC-Novice,

For the hydronic radiator, as the water loop are chilled water, no way to provide heating.
But since the simultaneous heating with cooling, happens in mild season, so electric heat of 1-2 kW could be an option. Then I need to manage not too many electric heating are on at a given time.

I need all the thermostat network together, and have a monitor on how many electric heaters are turn on, and give it a upper limit based on what power supply is available.

For MintJulep, thank you for your comment.

Changing the FCUs to water source heat pumps need modification of the chiller, boiler loop, controls, and the power supply distribution to each room?
Appreciate your insight on the feasibility.

My best regards
Dennis@2-pipe FCU.

 

[MintJulep]

Changing the FCUs to water source heat pumps need modification of the chiller, boiler loop, controls, and the power supply distribution to each room?

Probably.

 

[LittleInch]

I'm with Mint Julep. so what does it want / allow you to do?

A lot depends on the availability of data. DO you have individual room temps or know which ones get the complaints about being too hot / cold?

Can you section the building so that some gets cool water and other gets hot water?
Is there a time element to this in the shoulder months? i.e. needs heat from 6pm to 6am, then cooling from 8am to 4pm?

It's always easier to add heat than "cool"

How many rooms /FCUs are we talking about here?

But long term its either a 4 pipe system or a constant water temp flow and individual water air heat pumps either heating or cooling as required.

Do a study, give them options.

Or buy a bunch of fan heaters for those cold guests.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.