Канада - вертяки в мороз выдали 9МВт мощности вместо плановых 3000МВт

Helsinki, Finland
Helsinki has a well established district heating and cooling network, supplying 90% of the city’s
heat demand and an increasing proportion of cooling demand, and covering a range of
customer types. Although the heat network is mostly heated by gas-fired CHP and the cooling
network by absorption chillers, new plant such as heat pumps and storage can be and are being
integrated. In 2006, 84 MW of heat pump capacity (in 5 individual units) was integrated into the
existing system, covering 4% of the network’s total heat and 33% of total cooling.
The heat pumps’ sources, sinks, source temperatures and sink temperatures vary seasonally:
 In winter, heat is recovered from sewage and used to preheat the district return flow from
50°C to 62°C. This is lower than the network temperature, but in this way the heat pump
can run more efficiently. All cooling is provided directly from sea water (free cooling), so the
heat pumps are not used for this.
 In the summer the heat pumps operate to meet the cooling loads, with the heat extracted
from the cooling network being used to heat the heating network to the summer operating
temperature (88°C). Heat from the cooling network that is in excess of the heating network
heat demand is rejected into the sea.
The Helsinki scheme is an example of economically viable and technically successful
integration of heat pumps in heat networks. It operates without any grants or subsidies,
although it should be noted that this is partly due to a set of factors that are not entirely
applicable to the UK. These include the limited availability of natural gas in Finland, the
prevalence, experience and knowledge of district heating systems which lead to lower capital
and operating costs, and the demand for district cooling networks. Regarding this last factor, the
benefit of the heat pump is maximised due to the co-location of heating and cooling networks, in
which it carries out effective heat recovery. In the UK there are currently far fewer existing high
temperature heat networks to connect heat pumps to, and even fewer combined heating and
cooling networks. However, there is potential for new networks to integrate heat pumps in this

Heat Pumps in District Heating
25
way. Furthermore, from the industry consultation undertaken as part of this study, the use of
heat pumps in heat recovery from sewage is currently being considered in the UK.
Wandsworth, London
Wandsworth Riverside Quarter is a development of apartments on the banks of the Thames in
south-west London. The development will provide 504 apartments and substantial commercial
and leisure space when fully built out, the first apartments were occupied in 2013. An Aquifer
Thermal Energy Storage (ATES) system has been installed in Phase 1 of the development,
providing both space heating and cooling to the mixed-use buildings. Heat supply for domestic
hot water and heat pump back up comes from gas boilers and a gas CHP.
The ATES scheme consists of three heat pumps coupled to an aquifer below the site via an
open-loop system of boreholes. The heat pumps supply a peak cooling capacity of 2.25 MW
and a heating peak output of 1.2 MW. The aquifer warms over the summer due to the injection
of the waste heat from the cooling loads, leading to better heat pump performance in winter. In
the winter the aquifer is cooled as heat for the space heating is drawn out, and this cooling of
the aquifer means the summer cooling COPs are higher - or under ideal design conditions the
aquifer is cool enough to directly cool the chilled water. Space heating is supplied at 45°C.
Where the geology is suitable and regulatory consent can be obtained, the technical potential of
schemes similar to the Wandsworth ATES installation is high. ATES systems can achieve very
good COPs where there are heating and cooling loads approximately in balance over a year.
Furthermore, the function of the ATES as a heat sink means that no heat rejection plant is
needed for the building cooling system – a useful benefit is in dense city locations, especially as
it has become increasingly common for building occupants to make use of the roof space where
such heat rejection plant was typically put.
The capital cost for the Wandsworth scheme was high (around £2 million for 500 flats) –
however, in areas of high property value this cost is viewed as inevitable for obtaining planning
permission. Due to the interseasonal heat recovery leading to more ideal heat pump source
temperatures, ATES systems should have low operating costs. Achieving maximum efficiency
requires the building heating and cooling systems to be designed to allow the ATES to yield its
full potential. This requires a good understanding of system optimisation and good attention to
detail.
There are many successful ATES schemes in Holland and Belgium. ESCO operators are
actively seeking opportunities for application of the ATES approach in mixed use buildings in
the UK. Installations in areas of mixed domestic and commercial buildings could optimise the
balance of heating and cooling loads.
Brooke Street, Derbyshire
Brooke Street is an off-gas grid area on the edge of a rural village in South Derbyshire. A small
heat pump in district heating installation was carried out in 2012 to serve 18 existing local
authority flats (built in 1982), to replace individual electric heaters in each flat.
The replacement of the previous heating system was carried out due to residents’ complaints
about the high cost and poor control of electric storage heaters. The council was interested in
exploring renewable energy solutions, and obtained a RHPP grant to help fund the capital cost
of the installation. Building fabric insulation was improved where possible as part of the project.
The installation consists of three ground source heat pumps using 28 boreholes, coupled to a
common ground loop. The heat pumps supply heat at 55°C to a network, sufficient for space
heating through low temperature radiators. The network is raised to 60°C for a period every

Heat Pumps in District Heating
26
night to heat the DHW cylinder and remove Legionella risks. However, the previous electric
showers were not replaced, so the DHW cylinder does not serve these and hence DHW
demand is low.
This scheme is the only one of the case studies involving retrofit of not just central plant/network
but also components within homes. It is therefore useful to consider the process.
A couple of years on, the residents are very satisfied with the new system. There were however
a number of problems at the start. The project caused more upheaval in and around the flats
than the council had first envisaged, one reason being that other maintenance work needed to
be brought forward, and another being that the short time period in which the grant needed to
be spent meant that the scheme of works could not be planned for minimum disruption.
Residents initially did not understand how to best operate their new heating and DHW systems,
leading to higher operating costs than anticipated. It has also taken time for the council to
consider how best to charge for the cost of operating the system, in terms of how the fixed and
variable costs are passed through to the residents.
The above challenges do not concern the technical design of the scheme. Indeed, there is good
technical potential for energy and CO2 savings from heat pumps in heat networks in off-gas grid
areas such as this one, where the previous heating system is direct electric resistance heating
or storage heaters. However, one consideration arising from this type of system is how to
effectively heat and store DHW in schemes using medium temperature networks. In the
Derbyshire scheme, the heat pumps boost the DHW tank temperature from 55°C to 65°C once
per day, leading to high standing losses from DHW tanks. This raises the question of whether
the magnitude and frequency of the heating boost are necessary and whether legionella
regulations could be addressed using a more efficient solution. Similar schemes in the
Netherlands heat the DHW from the network directly at 55°C.
Duindorp, Netherlands
The scheme at Duindorp is relatively complex, with high capital costs due to the need to
purchase and install the central heat pump, the network and the distributed heat pumps.
Furthermore, the operating costs are also high. The operator of the Duindorp scheme
commented on the significant commitment arising from being responsible for the efficient
operation of 789 distributed heat pumps. Commonly, a key benefit of district heating for
housing providers is the reduction in maintenance responsibilities within flats/houses, where
getting access can be time consuming. The Duindorp setup loses this benefit.
Using seawater as the heat pump heat source has also been implemented in the UK (at
Portsmouth International Ferry Terminal), however in the UK scheme the central heat pump
produces high temperature heat directly. Although it poses challenges (corrosion, filtering and
restriction of inlet and outlet points by growth of seaweed) it could be a promising solution for
heat networks by the c