gledhill 120IND, Инструкции по проектированию, установке и обслуживанию

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Buffer vessels are simply a duplex stainless steel tank that contains a
volume of water. Buffer vessels are used in heating systems to decouple
the heat sources from the heat demands, in the same way a hot water
cylinder decouples the hot water demands from the boiler.
Buffer stores are recommended by heat pump manufacturers to ensure
trouble free operation of their appliances. They achieve this by presenting
the heat pump with a larger volume of water to heat which reduces
the amount of cycling. This in turn extends the life of the heat pump’s
compressor and by reducing cycling reduce running costs.
These buffer stores can be connected to air, water or ground source
heat pumps.
Buffer stores can be connected to either open vented or sealed systems as
they are designed to work at up to 3.5 bar. The systems that are connected
to the buffer store dictate the selection of system and components required
for safe operation, and this is the responsibility of the system designer.
Buffer stores are not suitable for potable water and should not be
used to feed any hot water outlets.
Direct & Indirect buffer stores
Direct buffer stores are heated directly by the main heat source only, eg.
heat pump, and do not incorporate electric heaters and therefore the
heating circuit flow temperature connected to the buffer vessel depends
upon the flow temperature of the heat source. This type of store is ideal
for the combination of a heat pump with under floor heating. Underfloor
heating operating at 30°C - 40°C.
Indirect stores enable connections to be made to the heat pump, heating
system and an additional heat source. This could be an oil or gas boiler
but not a solid fuel heat source because the heat exchanger is not of
the correct type. The additional heat is supplied via a heat exchanger
and therefore is hydraulically separate from the water in the buffer store.
An additional heat source is useful for extreme conditions when the heat
pump may not be able to supply the heat required and when it can top
up the store.
Flexible buffer stores
This type of buffer store has been designed with flexibility in mind. It
enables multiple heat pumps and/or separate domestic hot water and
central heating zones to be connected. For this reason the installation
diagrams in the following pages do not relate to this model. The installer
can choose how to install this product and blank off any unused
connections.
Weather compensation
Some heat pumps can use the external temperature to control the
temperature of the water supplied to the cylinder and therefore the
temperature supplied to the under floor heating. This can produce further
savings by eliminating the need for the thermostatic component of the
under floor heating manifold. Also it enables the heating system to run at
its optimum temperature, rather than running too hot for the conditions
at that time.
DESIGN
DESCRIPTION
Please Note:-
i) Any heat source, heat pump, boiler or other source used in a sealed
system must incorporate a certified overheat protection device and
the heat source should be certified for use in a sealed heating system.
All heat sources must have two independent temperature control
devices, for example, a control and an overheat thermostat.
ii) Any sealed heating system must have a means for accommodating
the expansion of the whole system volume including the buffer
vessel’s volume.
iii) Any heat source in a sealed heating system must be fitted with a
pressure relief valve (PRV), and there should be no isolating valve
between the PRV and the heat source.
iv) Any sealed heating system should incorporate an approved filling
method.
v) Should it be deemed necessary by the designer or installer to
incorporate a third level of protection against overheat, a manual
reset overheat thermostat can be fitted in the top thermostat pocket.
This coupled with the energy cut off valves for every heat source will
stop the buffer store overheating if all other devices fail.