fossil-free hall heating

Summary: 

The main alternatives to gas heating in industrial halls areheat pumps, the use of process waste heat, district heating, and biomass.For individual zones, electric infrared heaters are an option. Which solution fits depends on hall height, usage, internal heat loads, and available energy sources. In halls with machines and processes, the combination of waste heat utilization and heat pump is often the most economical way, provided the distribution system operates with low supply temperatures.

ECONOMICS

Why is it worth switching away from oil and gas?

Heating and air conditioning account for 30 to 50 percent of total energy consumption in industrial buildings, depending on usage.Four developments are increasing the pressure on fossil-fueled hall heating:Rising CO₂ costs:

• Austria and Germany are already pricing CO₂ from heating fuels nationally. With the planned EU emissions trading system for buildings and transport (ETS2), fossil heat will gradually become more expensive across Europe.
• Price risk: Gas prices fluctuate significantly. The energy crisis of 2022 has shown how quickly heating costs can change the calculations for a location.
• CO₂ balance: Emissions from hall heating count as direct emissions of a company. Customers and parent companies are increasingly demanding transparent reduction pathways.
• Lifespan: A gas heating system installed today will operate into the 2040s, a period when fossil heating is likely to be significantly more expensive.

OVERVIEW

What alternatives to oil and gas heating are available for industrial halls?

The following overview shows the common gas-free solutions and their key application conditions:

IN DETAIL

How do the alternatives work, and when are they sensible?

Heat pump: efficient at low temperatures

An industrial heat pump generates multiple times the heat from one kilowatt-hour of electricity, depending on the heat source and temperature level. It operates most efficiently when the distribution system can work with low supply temperatures. Classic warm air heaters and dark radiators are usually not designed for this. Therefore, simply replacing the heat generator is rarely sufficient.

An advantage in many halls: heat pumps can also cool. Where the hall overheats in summer, this saves the need for a second system.

What to pay attention to:Heat source (outside air, groundwater, waste heat), power connection capacity, supply temperature of the distribution system, and the combination with a photovoltaic system.

Utilization of waste heat: the energy that is already in the hall

In production halls, often more heat is available than assumed: machines, compressors, ovens, hardening and painting processes, as well as warm exhaust air from extraction systems. If this heat is captured and recovered, the demand for supplied heating energy decreases significantly. For heat pumps, waste heat is an ideal source because it is at a higher temperature level in winter than outside air.

What to pay attention to:Measure waste heat quantities instead of estimating, check the temporal availability (shift operation, weekends), and reliably filter contaminated exhaust air before heat recovery.

District heating: easy if a network is available

District heating does not require its own heat generator on site and takes up little space. Since it is usually delivered at high supply temperatures, it can often be connected to existing distribution systems. However, how climate-friendly it is and how prices develop depends on the respective network.

What to pay attention to:Connection options, connection costs, CO₂ factor of the network, and contract durations.

Biomass: high temperatures, high operational effort

Wood chip or pellet boilers provide high supply temperatures and therefore fit many existing heating systems. However, this is countered by fuel storage, delivery, ash disposal, maintenance, and regulations for dust emissions.

What to pay attention to:Space requirements, regional fuel availability, and emission limits at the site.

Electric infrared heaters: for zones, not for areas

Infrared heaters are inexpensive to purchase and respond immediately. They are a sensible addition for individual workstations or rarely used areas. However, when used extensively, they incur high electricity costs because they convert electricity directly into heat.

Hybrid solution: the gradual approach in existing buildings

Where a complete switch is not possible at once, heat pumps and waste heat take on the base load, while the existing boiler only covers peak loads. This immediately reduces gas consumption and emissions, and the boiler can be replaced later.

HEAT DISTRIBUTION

Why does heat distribution determine success?

In high halls, warm air rises. It is several degrees warmer under the roof than in the work area, and this is exactly where heat is lost through the roof and ventilation. A new energy carrier does not change this.

Therefore, an economical hall heating system without gas must solve three tasks together:

• Distribution: Delivering heat and cooling precisely where people, machines and processes need them.
• Generation: providing the required energy efficiently and cost-effectively.
• Recovery: utilising existing residual and waste heat before supplying additional energy.

Additionally: Heat pumps only work economically with a distribution system that operates at low temperatures. Thus, distribution is not only an efficiency issue but also a prerequisite for the transition.

APPROACH

How does the transition from gas to an alternative succeed?

1. Record the following details: heating load, current consumption, hall height, insulation, door openings and operating hours.
2. Measuring waste heat potential: Which machines, processes and exhaust air flows generate how much heat, and when?
3. Assessing the distribution system: Does it work with low flow temperatures, or does it need to be adjusted?
4. Selecting and sizing the system: factoring in summer cooling requirements right from the start.
5. Check what grants are available and work out the figures over the system’s lifetime: in Austria, for example, the Domestic Environmental Grant (UFI) may be an option, whilst in Germany it is the Federal Grant for Energy and Resource Efficiency in Industry (EEW). The terms and conditions change regularly and should be checked to ensure they are up to date before planning begins.