Heat Pump and Heat Recovery Systems For Industrial Applications – Decarbonising Heat Production To Achieve Net-Zero Targets

The UK’s ambitious Net Zero goal of 2050 means that businesses are under pressure to develop and implement decarbonisation strategies. Some sectors have already published their strategies and others are being urged to publish detailed plans. For many UK businesses, this means implementing radical changes to their existing operations, including those designed to facilitate the decarbonisation of heating.

Heating is vital to many industries such as food manufacturing, dairy, brewing and distilling, HVAC, petrochemical and pharmaceutical. Many businesses in these sectors utilise enormous quantities of energy to produce hot water and steam. In most instances, this is achieved by burning fossil fuels, resulting in significant greenhouse gas emissions and increasing operating costs.

One of the simplest ways to decarbonise heating is by recovering and repurposing waste heat from existing site processes to conserve energy and improve efficiency. In doing so, businesses can reduce their reliance on unsustainable fossil fuels, lower their carbon footprint and save money on energy costs.

In many cases, facilities generate cooling and heating either simultaneously or sequentially but the heating and cooling systems might had been designed to operate independently, leading to a missed opportunity for achieving optimal efficiency . Businesses are now striving to meet global warming targets, resulting in a shift in focus towards a more integrated approach between heating and cooling. This is an opportunity to repurpose hundreds and even thousands of kilowatts of energy typically rejected from cooling systems and boost them into useful heat for a small amount of additional energy input.

Recent developments have resulted in the implementation of heat pump technology to simultaneously produce cooling and heating or boost energy rejected from cooling systems into useful hot water to meet heating demands. A kilowatt of electrical energy input to a heat pump can generate more than three kilowatts of heat, which is more than three times more efficient than a gas boiler. This increases to over five kilowatts of heat when boosting waste heat from an existing cooling system. Heat pump technology can also be driven by renewable energy from solar, tidal or wind sources, helping to cut carbon emissions and save on operating costs.

Growing awareness and understanding of the benefits of integrated cooling and heating technology is leading to the early engagement of cooling and heating experts in new projects to optimise energy efficiency and reduce overall energy spend.  Identifying and utilising sources of waste energy has become a top priority for long-term sustainability, whether it involves designing new facilities, replacing traditional gas boilers with heat pumps at existing processing plants or integrating heat recovery systems into equipment. Heat pumps and heat recovery systems can radically improve a company’s performance while helping decarbonise their heat supply.

What is heat recovery and how can it be used?

Heating and cooling account for approximately 50% of Europe’s total energy consumption. According to the EU’s ‘Heat RoadMap Europe, a low carbon heating and cooling strategy 2050’ report from 2017, heating consumption represented 96% (6,110 TWh) of the final energy demand for heating and cooling in 2015 while cooling had a 4% share (242 TWh). Fossil fuels were the main source of heat production but heat recovery can represent a major opportunity to cut industry energy consumption and reduce its carbon emissions.

The report also highlighted that the industry makes up roughly 25% of the EU28’s final energy demand. Within this sector, process heating uses 1,920 TWh, which represents 60% of the industry’s energy consumption. A further 11% of the energy used by industry is allocated for space heating.

Heating in the industrial sector includes the generation of steam, hot water or other fluids for a variety of applications. It is possible to capture waste energy from industrial cooling and heating processes and use it for other demands including space heating, water heating, cleaning and other production processing. In this case, energy is transferred to a heat recovery system through a heat exchanger and then repurposed within the same process or facility. The heat can also be used externally; for example, the excess heat from cooling a data centre could be redirected for use within district heating networks to heat nearby housing developments.

Heat recovery aims to avoid heat loss that would otherwise be wasted to the environment. It is important to note that heat can be collected from a source at any temperature, whether it is at +20°C or -20°C. There are various types of heat recovery systems, ranging from basic heat exchanger units to sophisticated heat pumps. The latter uses a refrigerant circuit to boost the waste heat temperature to provide hot water for a variety of applications, including food and beverage production where it is used for product heating, pasteurisation and clean in place (CIP).

Heat recovery and heat pump systems work optimally when integrated into the design of a new building and/or process but can also be retrofitted into existing sites to extract the most out of any energy that is already being generated and rejected.

Simple Heat Recovery 

Heat exchangers can be added to new and existing systems for simple heat recovery. An example is temperature-controlled warehousing, where heat is recovered from the refrigeration plant oil coolers to warm glycol for underfloor heater mats or defrosting room coolers. Desuperheaters can also be fitted to heat water boiler feeds and process water.  For large capacity applications, some or all of the heat rejected by the refrigeration plant can be used to heat water up to 30°C or higher.

Industrial Heat Pumps

Where higher temperatures are needed, heat pump technology is able to boost hot water temperatures to +85°C or higher. A heat pump can provide combined cooling and heating or can also be added to an existing refrigeration system to boost heat previously rejected to the atmosphere.

Heat pumps can serve as efficient alternatives to gas boilers for many industrial processing and manufacturing applications with temperature requirements below +90°C. Where heating systems have been designed for higher temperatures, it is sometimes the case that gas is burned at more than 1000°C to generate steam at just 100°C to 150°C for distribution across a facility. Yet, this steam is often used to heat water to less than +90°C, making it a very inefficient process.

Heat pumps however, allow heating to take place efficiently at the lower temperature and with less harm to the environment in terms of CO₂ emissions.

Industrial heat pumps are thermal energy transfer devices that use the same electrically driven cycle used for refrigeration to efficiently capture heat from diverse sources and boost its temperature for repurposing elsewhere in the form of heating and hot water. Heat pumps were first developed in the 19^th century but advances in modern technology have made them more effective and efficient than ever before.

How Do Heat Pumps Work?

Heat pumps harness energy from sources such as refrigeration systems, industrial processes, rivers, air, sea or boreholes at relatively low temperatures (low-grade heat), and results in the cooling of the source fluid. Through additional power input in the form of electricity, the energy is then boosted through the heat pump cycle to generate warmer, high-grade heat. Despite requiring electricity, heat pumps typically generate three times the amount of heat energy they consume, boasting an efficiency of 300% or higher. This stands in stark contrast to traditional boilers, which often fall short of 100% efficiency.

Moreover, advanced heat pumps can simultaneously provide heating and cooling, pushing their efficiency to impressive rates, such as seven times the electricity input. These units are positioning themselves as viable alternatives to conventional fossil fuel-based heating systems.

The environmental footprint of heat pumps can be further reduced when they use eco-friendly refrigerants, like ammonia or carbon dioxide, and harness power from renewable energy.

What to consider when investing in heat pump technology

When replacing a boiler (or other fossil fuel based heating system) with a heat pump it is important to understand the heating demand profile. Boilers are often sized for the peak demand but the heating requirement is lower for the majority of the time.

Selecting a heat pump on the same principle can result in high initial capital costs and a long payback period. However, by understanding the heating load profile, it may be possible to add thermal storage to a system and use a smaller capacity heat pump. The thermal storage would provide the necessary increase in heat capacity for periods of peak demand and the heat pump would top this up during periods of reduced demand.

Other options to enhance heat pump performance include the installation of solar panels, a thermal battery or  thermal storage. These can generate and store the necessary power to operate the heat pump and avoid the need to pay for the electricity from the grid.

Application of Industrial Heat Pumps

UK food and beverage manufacturers are implementing heat recovery and heat pump systems that harness waste heat from refrigeration processes to generate heat for pasteurisation, CIP and process heating demands. There are a few examples below:

The IT infrastructure in data centres generates vast amounts of heat and requires cooling in order to avoid the equipment overheating. Cooling has traditionally been provided by air cooled chillers and the energy from both the IT equipment and chillers rejected to atmosphere. According to the think tank Energy Innovation, large data centres produce over 100MW of waste energy that can be capture and boost by heat pumps to heat over 80,000 homes.

Distillation industries also require substantial quantities of heat for the distillation process which constitutes over 80% of their fuel consumption, primarily from fossil fuels. The use of heat pumps can address both the production of heat and steam for the process and the recovery of the excess heat, offering a cost-effective alternative for removing carbon from their operations.

The Benefits of Heat Pump and Heat Recovery Systems in the Industrial Sector

Below is a summary of the primary advantages of installing heat recovery systems and heat pumps in the industrial sector.

• Reduced energy consumption. By harnessing the heat that is already being created as a by-product of a plant’s operations (or from the surrounding natural environment), it is possible to lower the amount of energy consumed for heating purposes. In many cases, a heat pump can supply all the heat a company will ever need, replacing gas boilers entirely.
• Lower running costs. Heat pumps can deliver more than three kilowatts of heating for one kilowatt of electrical energy. When cooling and heating occurr simultaneously, seven kilowatts of cooling and heating can be provided per kilowatt of electrical power. Energy is typically one of the largest costs for any business relying on cooling/heating operations, so reducing consumption will benefit the business’s bottom line.
• Fewer greenhouse gas emissions. The reutilisation and recycling of rejected heat leads to considerable reductions in the CO2 emissions, due to reduced need for electricity and gas. Heat pumps can also be powered by ‘clean’ energy from renewable sources, making them a zero carbon technology. A site could effectively experience a 100% reduction in their emissions immediately after installing an industrial heat pump.
• Future-proofed investment. In the face of the impending climate crisis, the government is imposing ever-stricter requirements on the environmental performance of industrial sites working in a range of sectors. High temperature ammonia heat pumps are exempt from the F-gas Regulation and represent the cutting-edge of sustainable performance as an investment not just in the future of a business but the future of the planet.
• Greener credentials. As well as being the most cost-effective way of managing energy consumption and complying with national and international environmental legislation, improving a company’s carbon profile positively impacts relationships with customers and can influence partnerships with like-minded organisations. Business that can demonstrate a commitment to reducing their carbon footprint and promoting sustainability have been proven to enhance their reputation and brand image.

The recovery and recycling of waste heat carry a lengthy list of benefits that can not only boost the performance of a plant but bring it into the 21^st century in terms of its environmental obligations.

A real case study – Confectionary Production Facility

Star have been designing heat recovery systems for chillers and central cooling plants for over 50 years as well as award-winning heat pumps for both district and industrial purposes. One notable project is a UK based confectionary factory that had been using a coal-fired steam generation plant to produce hot water for all its heating requirements.

Star was tasked with decreasing the energy consumption and operating expense of the chocolate factory. An electrical heat pump was selected as the best option to meet the site’s heating and cooling demands.

Star designed and developed a high-pressure heat pump system utilising ammonia as the refrigerant. The installation chills glycol to -5°C and utilises a portion of the waste heat to generate hot water at between +60°C and +65°C. The total high grade heating capacity of 1.25MW is generated with just over 100 kW of additional electrical input when compared to what would be needed for cooling only.

After changing both the original cooling and heating systems to the new heat pump plant, there was a £120,000 saving in electricity for the cooling and £143,000 reduction in heating costs.

Next Steps – Ensuring your business ‘Decarbonisation Strategy’ is right   

Recovering waste heat is an effective way for industries to meet their net zero carbon targets and reduce their energy costs. Heat recovery systems such as basic heat exchangers and more complex heat pumps can help business reduce their reliance on fossil fuels. They also improve energy efficiency by minimising the energy required to produce the same output. Both demonstrate a businesses commitment to sustainability and address the urgent challenge of climate change.

Star Refrigeration has always been committed to helping customers strike the right balance between capital costs and energy costs through the use of environmentally conscious solutions. Currently, we are helping end users with their Decarbonisation Strategy by providing expert advice and practical remedial actions to achieve energy and carbon targets. The sharp increases in energy costs over the last 18 months means users of electricity and gas should be identifying and addressing the root causes of their energy consumption. Here are a few tips to help you get started:

An expert’s survey of the site will highlight potential sources of waste heat and identify wider energy saving measures. Even a fairly large site consuming hundreds of thousands of pounds in gas and electricity can be appraised for just a few percent of the ongoing spend. Businesses must consider that often small improvements could make a big difference to the bottom line. Recommissioning alone could save over 5% of running costs, while an upgraded plant could save up to 30% (even 50% in some cases) of the total energy spend.

The Governement is extremely committed to decarbonising our industries and has recently announced the launch of the third phase of the Industrial Energy Transformation Fund. The fund is worth £185 million in grant funding to UK businesses for energy efficiency and deep decarbonisation studies and deployment projects.

For an initial review and assessment of your site’s energy saving potential, set up a meeting with Nicky Cowan by clicking here