Dimplex LA 12 MI, Installation & Technical Manual

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Section 5: DHW preparation with inverter heat pumps
Dimplex EC-Eau cylinder range
EC-Eau, the new range of unvented stainless steel
cylinders from Dimplex can supply all the hot water
required for the modern home, providing rapid fill baths
and invigorating showers to en-suite bathrooms and
other domestic appliances simultaneously. Offering low
running costs, reliable hot water and fantastic flow
rates, EC-Eau cylinders are available in a range of
capacities, so there is size to suit even the most
demanding household.
EC-Eau heat pump cylinders are specified with large,
high surface area heat exchangers, specifically sized to
match the requirements of Dimplex heat pumps,
optimising heat pump efficiency and reducing running
costs. The diameter of the EC-eau range has been
specifically picked for the UK market with a diameter or
580mm unlike many other cylinders available.
Supplied with an external expansion vessel for
improved reliability and reduced cylinder height, EC-
Eau standard cylinders are flexible to site and easy to
install.
Environmental sensitivity and efficient performance are
key attributes across the EC-Eau range, which boasts
60mm of low GWP insulation foam and innovative
measures
such as recessed immersions and
thermostats to reduce energy wastage. This combined
with the use of 100% recyclable stainless steel inner
components and a sleek black, hard wearing outer shell
manufactured from completely recycled materials
ensures the EC-Eau range looks as good as it
performs.
Dimplex ECS Combination DHW and Buffer
Cylinders
In addition to all the benefits of the standard cylinder
Dimplex can also offer a combination cylinder with a
DHW cylinder and buffer cylinder. This makes is easy
to retrofit a heat pump as the new combination cylinder
takes up the same space as the old cylinder.
The EC-eau range of combined buffer and DHW
cylinders have the buffer cylinder on top which gives
the following benefits:

The buffer acts as an excellent air separator,
and putting at the top of the cylinder means it
is likely to be one of the highest points in the
system allowing air to easily be removed.

The heat loss is reduced from the combination
cylinder because there is less of a temperature
gradient between the cylinder/buffer compared
to the cylinder/ambient air.
Volume
Outer
diameter
Cylinder
only
Combined
buffer and
cylinder
125 580mm
150 580mm
175 580mm
210 580mm
250 580mm
300 580mm
Table 7: EC-eau cylinders for use with the LA MI range
Heat pump power for hot water preparation
In addition to the space heating, the demand placed on
the heat pump for hot water production must be taken
into account when selecting the heat pump.
To meet normal comfort requirements, a peak hot water
consumption of approximately 60-70 litres per person,
per day, should be allowed, based on a hot water
temperature of 45°C.
Selecting a DHW cylinder
A standard DHW cylinder is not suitable for use with
heat pumps due to the small coil size. A heat pump
provides lower hot water temperatures compared to a
boiler. For this reason a heat pump cylinder needs a
larger coil to ensure that the heat can be transferred
from the heat pump in to the water within cylinder as
efficiently as possible.
For all heat pumps, the achievable cylinder temperature
is affected by the maximum flow temperature and also
the kW output of the heat pump. Since the kW heat
output of an inverter air source heat pump does not rise
with air temperature the LA MI heat pump can achieve
45°C in all of the cylinders shown in Table 8.
If a different cylinder temperature is required the
following must be taken into account. For each of
Dimplex‟s heat pump cylinders, a graph of kW input vs
The sizing should be based on the worst
day, with the coldest possible weather and
the maximum possible number of persons
using DHW. If this sizing method is not
suitable because it causes over sizing of the
heat pump, the end user should be made
aware that they may sometimes need to use
the immersion DHW boost which can be
activated from the wall mountable heat pump
controller.