District Heating   

District heating and cooling is a part of the future.

By centralising the heating and cooling in larger systems it is possible to supply many properties from one source with heating and cooling. In the future we will see many more of these systems as they open new possibilities for energy recovery.

The energy removed in air conditioning, data center cooling or display cases in the supermarket can be used to produce heat for hot water and heating. This is not any new technologies but with more focus on climate change and increasing energy prices the justification increases. As the complexity of the systems increase Measuring and Verification becomes ever more important but is an insignificant cost versus the cost of the chillers/heat pumps. A failure cost is often hundreds of times the measuring cost and ClimaCheck have many examples were millions of Euros has been saved by optimisations of district cooling/heating systems. You can find cases here.

There are many ways to “create” heat, but the most sustainable way is when heating and cooling is combined so the cooling demand in one application can be used to generate heat in other properties or vice versa if you like. By connecting many properties, the possibility to re-use the condenser heat from the chiller increase or if you like to use chilled water as a heat source for the heat pump.

There is also an increasing use of “Geothermal systems” using the ground to store energy between summer and winter or from day to night. This can allow heat pumps to cool down the ground in the winter (resulting in better COP than an ambient air heat source at the same time as the system offer free-cooling from the ground over part of the cooling season (this also reload the ground for next winter). When ground temperature passes the temperature usable for “free cooling” the chiller/heat pump can be operated as chiller and has an excellent low temperature water from the ground for the condenser if there is excess heat that cannot be re-used for hot water production.

Annex 52 under International Energy Association is focused on long term measurements in geothermal systems. ClimaCheck is participating in this Annex – you can read more here.

It is important to ensure that these large systems perform as efficient as possible, otherwise the investments in distribution nets and their losses will not be justified. When there is a possibility to create both heating and cooling there will be a significantly reduced environmental impact and reduced operating costs. But as the complexity increase it will make it even more important to analyse performance to avoid waste of energy and reduced reliability.

ClimaCheck is used in district heating and cooling plants to make sure the equipment runs well and stay optimised.

It is usual that the chillers and heat pumps in these large plants are running long hours so even a few extra percent energy consumption means a lot of money and CO2 emissions. Sadly, it is common potentially efficient machines run far from optimal and consuming to much energy. ClimaCheck can be a part of the solution to optimise district heating and cooling plants through real time performance analytics, necessary in any optimisation project as well as for early warning if any part of the system loose efficiency.

Even if state of the art chillers/heat pumps are used , it is common that energy consumption can be reduced 10-30% by correction of undetected problems and low-cost optimisation. ClimaCheck can be set up as stand-alone with it’s own sensors or as an “integrated” solution with data from existing BMS/Scada systems and performance and efficiencies can also be visualised in the existing user interphase for operational staff.      

Large District heating/cooling plant in Sweden

ClimaCheck was installed on four heat pumps with 20-25 MW heating capacity – also used for district cooling. ClimaCheck detected a problem in one of the heat pumps that had just been overhauled by supplier and stated to fully operational. Evaporator efficiency was below expected, and compressor was getting carried over liquid.

After significant discussion the supplier agreed to take action and the evaporator was investigated. The issue was located to an oil-clogged demister in the evaporator causing a pressure drop but also resulting in the problem that the open parts had a velocity resulting in liquid droplets being transported through and hitting the impeller rotating at 9000 rpm. This would have caused a rapid wear down of impeller if not caught by ClimaCheck.

Casinos in Asia

In a price winning chiller optimisation project in Asia three large chiller plants with a total capacity of 350 MW cooling for hotels, malls and casinos were optimised.

ClimaCheck performance analysing was a key component in the project to identify opportunities to save energy in the re-commission process. The project included introduction of predictive maintenance based on ClimaCheck performance monitoring, vibration monitoring and regular oil analyses. The 24/7 monitoring results in lower failure costs as deviations are picked up early and maintenance are done when there are indications rather than based on hours of operation. A time schedule result in unnecessary tear down costs and does still not guarantee that problems does not cause failures.

Real time performance analysing is also an almost necessary tool for optimisation as optimisation always includes a step by step approach to identify the optimum balance of different parameters i.e. increasing flow cost pumping/fan power but also have an impact on compressor power there will always be an optimum and without real time performance data of process performance it becomes a huge challenge to identify optimum by random testing without quick feedback on compressor, condenser, evaporator response to the change and the total efficiency. 

KTH – Royal Institute of Technology

Data center cooling with heat recovery to district heating grid in University Campus.

ClimaCheck was used in Royal Institute of Technology’s commissioning of their two new chillers and two heat pumps that is supplying the system with heating and cooling their data center. By optimising controls energy consumption was decreased with 26% and unstable operation occurring at some conditions was avoided all by adjusting controls based on the observations in real time of performance with different combinations of settings.

The energy graph shows the changes in energy consumption from the start and to stable operation.

Yellow line – Outdoor temperature

Red bars – Energy consumption per 24 hours

Blue line – Energy consumption based on energy signature before optimisation (=predicted consumption)

Red line – Energy consumption based on energy signature after optimisation

Result – Savings of 2400 kWh/day (26% less energy consumption)

During the validation phase (see graph) another calibration was done, and energy consumption was lowered even more.  

If you want to know more about how to minimise energy consumption, maintain energy efficiency and improve the performance of facilities heat pumps, chillers and air conditioning.

You are always welcome to Contact us for more information!

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