Cold local heating - ratiotherm Smart Energy Systems

Q: Is it even possible to heat with cold local heating?

Yes, with cold local heating you can heat your home perfectly. The difference to other heating systems lies in the constant supply of low temperatures (10-40°C). In the past, the energy requirement for a single-family home was about 1/3 higher than it is today. This is due to more efficient house construction with energy-saving systems. Today, we simply do not need as much heat as we used to. Underfloor heating, for example, is much more energy-efficient and is used in many homes. The basic idea behind cold local heating is low-level heat distribution. The higher the temperatures, the greater the losses. Therefore, the heat is distributed to the building at 10–30°C. Cold local heating works in combination with heat pumps. They efficiently bring the low temperatures fed into the system to the desired level.

Q: Is there any financial assistance available for switching to cold local heating?

Yes. The amount of the subsidy depends on whether your house is an existing building or a new build. In existing buildings, the oil or gas heating system must be completely removed. In new buildings, you use energy-efficient heat pumps directly. Furthermore, subsidies are available for both network operators and end customers. Depending on the ownership structure of the local heating technology, network operators and end customers can apply for a wide range of subsidies. Individual advice is required for this – we are happy to help. The BAFA subsidy program Wärmenetz 4.0 provides funding for four modules: • Financial support for a feasibility study • Implementation • Acquisition • Participation of the scientific community

Q: Is purchasing cold local heating cheaper than existing heating systems?

The ecological balance of cold local heating is better. Lower feed-in temperatures mean efficient and renewable heat utilization. When converting from old to new systems, it makes particular sense to switch to cold local heating. The cost savings become apparent in the medium to long term through energy savings.

Q: What is an area network?

An area network refers to the combined full supply of electricity and heat. Similar to a self-sufficient "island supply," an area network uses energy generated by photovoltaics or electricity from a CHP plant and simultaneously uses the heat produced for heat supply. An area network can supply itself without external assistance. Energy suppliers often expand their electricity and heat supplies by providing fiber optic connections for the internet and water supply.

Q: Can cold local heating be combined with solar thermal energy?

Yes. Cold local heating can be combined wonderfully with solar thermal energy. Solar thermal energy is particularly effective during the summer months, whereas a conventional network suffers significant losses during this time. Cold local heating and solar thermal energy are therefore particularly attractive partners, both for network operators and end customers.

Q: Do you still need a hot water tank if you use cold local heating?

Yes. You will always need a hot water tank when using cold local heating. The heat pump requires an intermediate buffer, the capacity of which depends on the comfort standard of the building. A normal shower, for example, requires less energy than a rain shower with numerous water jets and additional functions. Our Oskar stratified storage tank combines your heating and hot water services in an energy-efficient and cost-effective way.

Intelligent local heating

The term “cold local heating” refers to local or district heating networks that operate at a temperature level of less than 30°C. These networks have been increasingly used in recent years because they combine a number of advantages and, under certain conditions, can greatly reduce the energy and emissions footprint of modern residential areas.

In principle, all alternative network forms (“cold local heating”) belong to anergy networks and are differentiated according to the temperature levels of the supply and return flows. The frequently used term “intelligent local heating” is more of a collective term that describes the fact that a network no longer has to be operated at high temperatures due to the lower heating loads of buildings. The temperature level required for heating and hot water in buildings is usually provided by decentralized heat pumps in the buildings. These use environmental heat at low temperatures, with renewable energies or surplus electricity increasingly being used for operation.

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Benefits | Strategies | Application examples | Looking ahead

The advantages of cold local heating systems at a glance:

Lower grid losses
Network losses are a loss-making business for many local heating operators, especially in the summer months when there is little demand for heat in buildings (often only hot water). The reduced temperature in cold local heating networks reduces network losses by up to 50% and significantly increases efficiency in summer operation.
Low-temperature heat becomes usable
Regardless of whether the low temperature (10-30°C) comes from industrial waste heat, wastewater, solar thermal energy, or near-surface geothermal energy, this energy can be efficiently distributed in a cold local heating network and converted into usable heating energy.
Decoupling the network from individual requirements of individual
In conventional local heating networks, the consumer with the worst heating system or the most unfavorable location in relation to the heating plant determines the flow temperature for the entire network. When decentralized heat pumps are used in cold networks, the system temperature and individual flow requirements are decoupled from each other, as the decentralized heat pump ensures the individually configurable temperature rise for each property.

Nahwärme-Wärmepumpe WP Grid-HiQ vom Hersteller ratiotherm

Cold local heating systems with ratiotherm heat pumps

Our heat pumps are a patented and clever combination of a transfer station for direct heating or hot water preparation via a local heating network and an integrated heat pump, which can perform these tasks alternatively or additionally – for maximum flexibility in local and district heating networks.

Find out more now!

The following strategies can be implemented in cold local heating systems:

Network strategy: purely cold operation – the original form of cold local heating

The flow temperature in this so-called source network is between 8-12°C all year round, which means there is no heat loss in the network. The use of uninsulated pipes means that additional energy can be absorbed “on the way to the end user,” which makes it cheaper to tap the actual source (probe field, groundwater wells, etc.). However, this requires a relatively large amount of electricity to operate the decentralized heat pumps. These networks use only environmental heat at very low temperatures and cannot be supported by additional energy sources. Existing buildings cannot usually be integrated into such networks, or only with great difficulty, as the heating loads are usually too high. This is the most inflexible type of anergy network.

Network strategy: Cold/warm operation depending on the season

In winter, the network is operated at a flow temperature of 60-85°C, just like a conventional network. This means that the heating load of the buildings can usually be covered completely and directly without the use of a heat pump. In this operating mode, hot water is also generated directly and exclusively via the local heating system. When the outside temperature reaches approx. 12°C and above, the network is switched to summer mode and runs at a flow temperature of 10-30°C. The network temperature is preheated via a heating center using solar thermal energy or other energy sources (CHP, wood chips, etc.). The big advantage: the solar thermal component can be maximized. Hot water preparation and any “residual heating loads” in the transition period are handled by the decentralized heat pump within each individual building. In networks where ratiotherm heat pumps with HiQ technology are used, flow temperatures of 10-55°C are possible, depending on the heat pump type. This is ideal for mixed-use developments (new and existing buildings), as the heating loads in winter can be almost any level regardless of the heat pump’s output, because the heat is transferred using a classic district heating transfer station.

Network strategy: flexible operation depending on the outside temperature

With this strategy, the flow temperature in the local heating network is always maintained depending on the outside temperature, flowing or sliding between 10-50°C, comparable to the heating curve of a central heating system. The buildings must be designed in such a way that this temperature is sufficient for complete heating. The heating energy is transferred directly to the heating circuits by means of transfer stations within the specialized heat pumps. Hot water is generated all year round by the heat pump located in each building, with the local heating system providing the preheating of the domestic hot water. The network’s heat is generated in a heating center using a mix of solar thermal energy, CHP, and conventional combustion systems (biomass, oil, gas). The sliding strategy is primarily suitable for new buildings.

Network strategy: Return cooling for optimization of network inventory

In large district heating and local heating networks with high connection densities, there is often a problem whereby the temperature differences (spread) between the flow and return do not meet the specifications or requirements of the local heating network operator. The network temperatures in the return are often too high, which hinders energy transport in the network. It is therefore advantageous for the district heating operator if the return flow is cooled down accordingly. This can be achieved by installing an additional network branch. This uses the return flow of the existing network as the flow and cools it down using decentralized heat pumps in the individual buildings. This technical option offers many variants, and we would be happy to advise you on this.

Cold local heating is ideal for the following applications:

For municipalities and cities, as an attractive model for decarbonization in residential construction
For municipal utilities, as an additional business model – especially in combination with a local area network
For companies in the contracting sector, as an efficient solution for cost-effective heat supply
For industrial companies to generate additional revenue from waste heat or to save energy used for cooling

Looking ahead

Why you should opt for cold local heating

Heating network subsidies: The combination of heat pumps and heating networks offers a wide range of subsidy options. The stated goal of the heating transition is reflected in the currently very attractive subsidy rates for the use of central and decentralized heat pumps. However, the subsidy landscape is constantly changing, so we would like to take this opportunity to point out our telephone consultation service on the subject of subsidies, you can find more information here.
In the neighborhood, implementation can achieve a very low primary energy factor, which makes connection to the heating network very attractive for homeowners, as the network connection already meets all requirements for a proportionate supply of renewable energies.
If we consider the cold heating network as an approach for supplying neighborhoods, the topics of area networks and customer installations come into play. This involves the holistic supply of electricity and heat to neighborhoods. This is currently the supreme discipline and is the key to sector coupling in modern urban development. ratiotherm would be happy to show you corresponding concepts and implementation methods – please feel free to contact us.

FAQ: Questions & answers about cold local heating

Is it even possible to heat with cold local heating?

Yes, with cold local heating you can heat your home perfectly. The difference to other heating systems lies in the constant supply of low temperatures (10-40°C). In the past, the energy requirement for a single-family home was about 1/3 higher than it is today. This is due to more efficient house construction with energy-saving systems. Today, we simply do not need as much heat as we used to. Underfloor heating, for example, is much more energy-efficient and is used in many homes. The basic idea behind cold local heating is low-level heat distribution. The higher the temperatures, the greater the losses. Therefore, the heat is distributed to the building at 10–30°C. Cold local heating works in combination with heat pumps. They efficiently bring the low temperatures fed into the system to the desired level.

Is there any financial assistance available for switching to cold local heating?

Yes. The amount of the subsidy depends on whether your house is an existing building or a new build. In existing buildings, the oil or gas heating system must be completely removed. In new buildings, you use energy-efficient heat pumps directly.
Furthermore, subsidies are available for both network operators and end customers. Depending on the ownership structure of the local heating technology, network operators and end customers can apply for a wide range of subsidies. Individual advice is required for this – we are happy to help.

The BAFA subsidy program Wärmenetz 4.0 provides funding for four modules:
• Financial support for a feasibility study
• Implementation
• Acquisition
• Participation of the scientific community

Is purchasing cold local heating cheaper than existing heating systems?

The ecological balance of cold local heating is better. Lower feed-in temperatures mean efficient and renewable heat utilization. When converting from old to new systems, it makes particular sense to switch to cold local heating. The cost savings become apparent in the medium to long term through energy savings.

What does cold local heating mean for the ecological balance?

The use of cold local heating means that neither oil nor gas are considered as energy sources. This makes an extremely significant contribution to the ecological balance. Cold heating only works in combination with energy-efficient heat pumps. Network operators have hardly any losses, as they only supply the energy that is actually used by the end consumer.

What is an area network?

An area network refers to the combined full supply of electricity and heat. Similar to a self-sufficient “island supply,” an area network uses energy generated by photovoltaics or electricity from a CHP plant and simultaneously uses the heat produced for heat supply. An area network can supply itself without external assistance. Energy suppliers often expand their electricity and heat supplies by providing fiber optic connections for the internet and water supply.

Can cold local heating be combined with solar thermal energy?

Yes. Cold local heating can be combined wonderfully with solar thermal energy. Solar thermal energy is particularly effective during the summer months, whereas a conventional network suffers significant losses during this time. Cold local heating and solar thermal energy are therefore particularly attractive partners, both for network operators and end customers.

Do you still need a hot water tank if you use cold local heating?

Yes. You will always need a hot water tank when using cold local heating. The heat pump requires an intermediate buffer, the capacity of which depends on the comfort standard of the building. A normal shower, for example, requires less energy than a rain shower with numerous water jets and additional functions. Our Oskar stratified storage tank combines your heating and hot water services in an energy-efficient and cost-effective way.