> if not a heat pump
Most heat pump installations in Europe are air-to-water systems fitted to use the existing piping in old homes and is used only for heating. Such installations can, in theory, be used for cooling, but very inefficiently.
Most heat pump installations in Europe are air-to-water systems fitted to use the existing piping in old homes and is used only for heating. Such installations can, in theory, be used for cooling, but very inefficiently.
I'm not sure thats true.
Most aircon in "warm" europe is standard split aircon
The "heatpump" shit that the UK is sorta looking at is as you describe. However its half the price to install "aircon" over heatpumps (because grants, amongst other things)
Like most recently refurbished offices will use normal aircon (certainly all the one I have worked in)
I've been doing some research into this, because I would ideally like to get this system so I can make use of the existing radiators in my old house, but I do also want to have the option of cooling my home. It does seem like Fan Coil Units (FCUs) are an option for this. Anyone have experience with these? Are they really inefficient compared to standard air-to-air units?
The possible real fixes are either to section off your water circuits in summer, and only run the properly cold water through FCUs, wall or ceiling loops.
Or to get a multisplit heat pump, use a normal refrigerant-air indoor unit to cool and a refrigerant-water indoor unit to heat the water loops.
In that scenario, are FPUs a good option? Are there other drawbacks?
Even then, there is a fair limit in cooling and efficiency you can get from them because of the lack of phase changes occurring.
If you have a balanced mechanical ventilation (both inlet and outlet) that would be one of the best options to condition the whole house without putting air conditioning units everywhere. Having said that, we turn on the air conditioning in the attic during hot days which removes the biggest heat and moisture from the house. Next up is installing more sun blinds to prevent the heat from entering in the first place.
Insulate all piping properly, the outdoor part will freeze in winter, and the indoor part will drip in summer if you don't. The best products for this are foamed rubber based. Make the insulation seamless with the right glue or tape, every opening will drip.
Add manual or automatic valves to shut off the heating loops in summer, so you don't accidentally get cold water in there. Your cold water loop might also need an extra circulation pump, depending on how you run your piping, but that's hard to say without a lot more detail.
FCUs are available in the same form factors as indoor units for refrigerant-based systems, including a thermostat remote control, e.g. https://www.sinclair-solutions.com/files/user-manual-en/fan-... . But get one from the manufacturer of your outdoor unit, so the communication lines work, e.g. so the indoor unit can instruct the outdoor unit to start/stop/regulate.
You just have the added equipment and maintenance for the water/glycol loop vs an air to air system that only pipes refrigerant around. Fan coil units or VAV boxes are the usual terminal units for commercial HVAC systems that have a chilled and hot water loop, VAVs are used in a system with ducted AHUs and FCUs are used for apartments (stacked FCUs with vertical supply/return risers) or spaces not served by ducted air handlers for whatever reason.