How Hotels Can Slash Their Energy Bills

In a year when hotel revenue from guests and conferences will be substantially lower than planned, seeking out cost savings suddenly becomes more important than ever. An investment in the latest energy-efficient technology that combines heating and cooling into one system can reduce a hotel’s total electricity usage by 44%.

A time of economic challenge for hotels

Hotels are slowly beginning to reopen in Norwegian towns and cities as some of the coronavirus crisis emergency measures are lifted. But with the borders still essentially closed for tourists, it could take a long time for revenue to return to pre-corona levels. Even if—as some travel industry bosses hope—domestic tourism increases this summer, hotels will be left with an inevitable reduction in their expected revenue for 2020, and possibly beyond.

At the same time, we are still in the midst of a climate crisis. If we are to meet the challenging goals of the Paris Agreement, drastic change is needed in every part of society. For a hotel, that change could be good for business as well as the environment. A survey of 72,000 guests by one leading global hotel chain revealed 33% prefer hotels with environmental and social programs. It jumped to 44% for younger guests.

New research from the HighEFF research centre shows that hotels can play their part in tackling the climate crisis and take a substantial bite out of their operating costs by switching to a CO₂-based HVAC system. Given the two major challenges we face today, that’s a win-win.

One system for the complex requirements of hotels

Hotels are about so much more than just the guest rooms. They are buildings with complex systems for hot water, heating and cooling. Different parts of the hotel will have drastically different requirements at different times. Because of this, the industry standard has been to use separate systems each dedicated to a specific function. However, even if each individual component is energy-efficient, a vast amount of energy is wasted when seen from a total system perspective.

Combining all a hotel’s thermal systems into one single system that can provide heating and cooling gives far greater efficiency. That means lower energy usage, lower costs, and less impact on the environment.

The first “all-in-one” CO₂ heat pump was installed in a Norwegian hotel in 2018. A 63% reduction in the use of electricity for heating and cooling was achieved in its first two years of operation. For an average hotel, this represents a 44% reduction in total electricity usage.

How combined heating and cooling works

Silje Marie Smitt has spent the last few years in the HighEFF research centre working on “all-in-one” CO₂ heat pump systems for hotels as part of her NTNU-funded PhD. She explains that the efficiency gains come from taking advantage of simple heat transfer concepts: “When cooling is required, the heat that would otherwise be wasted is removed, stored and used when and where the heat is required. That means heat can be recovered from ventilation cooling and be used for room heating and hot water production.”

Read more: “All-in-one” Thermal Solutions for Heating and Cooling in Hotels

Within the system, working fluids perform the task of upgrading the thermal energy from cold to hot and transfers it from one place to another. Previously CFCs and HFCs were among the substances used for the job, but they have since been prohibited due to their environmental impact.

“CO₂ is an ideal natural working fluid for heat pump systems and commercial refrigeration. It covers a wide temperature span within the same cycle, typically from -30° to 90°C,” says Petter Nekså from SINTEF Energy Research. Although CO₂ is often cast as the villain in the climate change debate, its use as a natural working fluid is a positive one. “Contrary to many other heat pump systems, CO₂ as a natural working fluid is often a recovered by-product from other industrial processes,” adds Petter.

Heat storage reduces peak demand

Another benefit of heat storage is the ability to shift energy demand and reduce peak loads. Providing hot water accounts for 40-70 % of a typical hotel’s total energy usage, but a lot of that demand is concentrated in two peaks during the early morning and late evening. Heat storage provides a buffer to cover excess demand during these times, helping the hotel to avoid peak energy tariffs. In addition, there are operational savings to the hotel’s thermal systems and an increase in operational stability.

How much can hotels save?

As part of HighEFF research, the Scandic Hell hotel in central Norway achieved a 63% reduction in the use of electricity for heating and cooling in its first two years of operation. The expected payback time depends on a hotel’s current consumption level. As the technology is not yet available “off the shelf,” payback is currently between 3 and 7 years. Ongoing HighEFF research aims to bring that time down by increasing the availability of the technology.