Introduction
13
ARTUS™ Technical Manual 9690348 v3_04_2020
Waterside
Water Coil
All units utilise large surface area coils, ideally positioned to optimise heat transfer and airflow. Each coil is manufactured
from high quality copper tubes with mechanically bonded aluminium fins and are circuited from headers to ensure low
water pressure drops. The Artus uses a three sided wrap around heat exchanger, maximising heat transfer area whilst
keeping a compact footprint. There are two distinctly different coil designs available:
Option 1. 2 pipe, 2 port PIC valve single mode of heat transfer (cooling or heating)
The first option available from Airedale is a single coil with an integrated PIC valve.
Option 2. 4 pipe, 2 coils segregated cooling and heating with 2 port PIC valves
The second option is segregated coils for cooling and heating. This enables the two coils to be independent to each
other. This is a conventional method designed for retrofit situations. The cooling coil has both the high and low flow
options whilst the heating coil is based on a single flow design. The water flow going through each coil is controlled by
an integrated PIC valve.
Option 3. Cooling and heating changeover system
Option three consists of a common combined coil for both cooling and heating. The combined internal heat exchanger
is shared between the building cooling and heating circuits i.e. they are not hydraulically separated. The unit uses a 3
port control valve to switch between the building cooling and heating circuits on the return sides of the heat exchanger.
An integrated PIC valve on the supply side controls the flow of water to the coil in both cooling and heating mode.
The advantage of this set up is that lower water temperatures can be used on the heating circuit i.e. rather than
using a conventional boiler system with a supply water temperature of 70°C for example, a much lower supply water
temperature of say 35°C can be used to thermally match the capacity of the cooling circuit. This has system efficiency
benefits in terms of opening up the potential to use a condensing boiler or heat reclaim device, instead of a less efficient
heat source running at higher water temperatures as is the case with hydraulically separated heat exchanger volumes.
It is important when using this type of unit configuration to ensure that potential inhibitors and glycol are prevented from
migrating from one circuit to another. When designing the system, ensure one pressurisation unit is used for both circuits
and the same static pressure is seen at the pump inlet on both circuits (i.e. pumps on same vertical level).
One of the following options should be utilised:
•
Ensure the same glycol concentration is used in both circuits.
OR
•
Integrate an intermediate heat exchanger on the cooling circuit so that the glycol solution is contained within the
system (see basic system layout diagram for reference).
High flow coil
•
Optimised for design flow rates above 0.1l/s
•
Typically 3-5K waterside ΔT cooling
•
Relatively high heating inlet water temperatures of
45°C and above.
Low flow coil
•
Optimised for design flow rates below 0.1l/s
•
Typically 6-8K waterside ΔT cooling
•
Relatively low heating inlet water temperatures of
below 45°C.
There should never be more than 2.5 Barg difference between the heating and cooling circuit
operating pressures.
CAUTION
Comfort
ARTUS™
