ALTERNATIVE FOR CLIMATE CHANGE IN AIR CONDITIONING SYSTEMS | THERMAL DISTRICTS

INPAL
Nov 22
4 min read

Before discussing the solution, we must understand the magnitude of the problem. High energy consumption in the cooling and heating of buildings accounts for global electricity consumption (up to 40% in commercial buildings in some regions).

Greenhouse Gas (GHG) Emissions: These emissions are twofold:

Direct Emissions: Due to refrigerant leaks (fluorinated gases such as HFCs), which have a global warming potential thousands of times greater than CO₂.
Indirect Emissions: From the burning of fossil fuels in power plants to generate the electricity that powers individual air conditioners.

Urban Heat Island Effect: Conventional air conditioning systems expel heat outside, raising the temperature of cities and creating a vicious cycle where more cooling is needed.

UNDERSTANDING THE PROBLEM, WHAT IS A THERMAL DISTRICT?

It is a centralized thermal energy distribution network (cooling and heating) for a group of buildings, similar to how a drinking water or electricity network works.

Buildings | District Heating — THERMAL DISTRICT.

The central concept is that each building has its own boiler and cooling system, while a central plant produces chilled water (cooling) or hot water (heating).

The water is distributed through a network of insulated underground pipes to the connected buildings (offices, hospitals, universities, shopping centers, residences, etc.). Each building has an energy exchange substation, which takes the cold (or heat) from the network and transfers it to its own indoor air conditioning system.

WHY ARE HEAT DISTRICTS AN ALTERNATIVE TO CLIMATE CHANGE?

District heating offers fundamental advantages such as massive energy efficiency. A large central plant is more efficient than hundreds of small individual units. It can use high-efficiency technologies that would be economically unfeasible for a single building.

BUILDINGS QUALIFIED FOR THE INSTALLATION OF DUCTS IN A HEATING DISTRICT.

Not all buildings reach their peak demand at the same time. Diversification of the central plant load can be sized for a capacity lower than the sum of the individual maximum capacities, optimizing the use of resources.

FLEXIBILITY IN THE USE OF ENERGY SOURCES

This is perhaps its greatest climatic advantage. A thermal district does not depend exclusively on electricity. It can use:

Waste Heat: Recover waste heat from industries, waste incineration plants, or power plants.

Renewable Energy:
Geothermal: Use the constant heat from the ground.
Biomass: Use renewable organic fuels.
Solar Thermal Energy: To heat water.

Seawater, Lakes, or Rivers (Free Cooling): In suitable climates, cold water from natural sources can be used directly in the system, drastically reducing electricity consumption.

DISPOSAL OF POTENT REFRIGERANTS (HFCS)

The central plant can use natural refrigerants with low or zero impact on global warming, such as ammonia, or even water (in absorption systems). This eliminates the risk of massive HFC leaks from thousands of units scattered throughout the city.

For Thermal Storage, it is technically and economically feasible for a thermal district to incorporate large ice or chilled water storage tanks.

This allows cooling to be produced at night, when electricity demand is low and, in many grids, electricity is cleaner (higher share of renewable energies such as wind power). This cooling is stored and used during the day, flattening the electricity demand curve and avoiding the use of coal or gas plants during peak hours.

REAL EXAMPLES AND SUCCESS STORIES

Manhattan, New York: One of the largest systems in the world, it provides steam and chilled water to more than 1,800 buildings, using a combination of cogeneration and free cooling from the Hudson River.
Paris, France: The Climespace system cools iconic buildings such as the Louvre, using cold water from the Seine River and large ice storage plants.
Toronto, Canada: The Enwave system uses cold water from the depths of Lake Ontario to cool the financial district, reducing electricity consumption for cooling by 90%.
Medellín, Colombia (Latin American case study): The La Alpujarra Thermal District cools government buildings. It is an example of how this technology is viable in tropical climates, achieving energy savings of over 30% and significantly reducing emissions.

District heating systems present many challenges and considerations, especially in developing countries.

High Initial Investment: The construction of the pipe network and central plant requires significant capital.
Long-Term Urban Planning: This infrastructure must be planned for new developments or renovations of existing areas, requiring a vision spanning decades.
Regulatory Framework: Public policies are needed to encourage its development, such as stricter energy efficiency standards or tax benefits.

Thermal Districts represent a shift in mindset from inefficient, electrified individual air conditioning to optimized, multi-energy collective air conditioning. They are not a futuristic technology, but a proven, scalable solution that fully addresses the main problems of the climate impact of air conditioning: efficiency, energy sources, and refrigerants.

Its implementation is one of the most powerful strategies for decarbonizing the building sector and creating more sustainable cities, serving as a fundamental pillar in the transition toward an urban energy model compatible with the fight against climate change.