One major avenue
for industrial decarbonization is replacing the direct burning of fossil fuels with
industrial heat pumps for process heat. This is one of the main methods of
industrial electrification. Industrial heat pumps are deployed for low-temperature
and high-temperature applications. Industrial heat pumps can also help
decarbonize district heating. About 95% of industrial boilers are powered by
fossil fuels (85%) and biomass (10%). Currently heat pumps provide 5% of global
industrial heat. That is set to grow. By
2030 they are expected to supply 10% of global low and medium-temperature industrial
heat. or heat below 200 degrees C. They can be used in many kinds of
industries, such as breweries, chemical plants and refineries, food and beverage,
and pulp and paper industries. they can be used at different temperature ranges. Use cases can vary considerably depending on the
project. Global investments are estimated to be between $12 billion and $21
billion by 2030. A March 2024 McKinsey & Company report notes:
“The trajectory of these investments is toward bigger
installations. Today, the majority of investments in industrial heat pump
installations go toward smaller and medium-size applications (up to five MWth)
and temperatures from 80°C to 100°C because lower-temperature applications are
more likely to provide a positive business case. However, large-scale
industrial heat pumps (more than five MWth) with temperatures higher than 100°C
are expected to become increasingly important in the future. District heating
is also expected to remain an important segment for industrial heat pumps, at
more than a third of the market in 2030.”
Industrial
heat pumps can be defined as heat pumps with power sizes beyond 200 kilowatts
thermal (kWth). Heat pumps are powered by electricity, which may be low-carbon
electricity. They can be a ‘no-brainer’ for low-heat and medium-heat
applications where they can be 3 to 5 times more efficient than traditional boilers.
Thus, they can be a good efficiency investment, with savings down the line
after upfront costs are recaptured. This eventual cost advantage combined with the
decarbonization benefits of heat pumps is leading to growth in industrial heat
pump manufacturing and deployment. McKinsey and Company expect annual growth to
remain above 15% through 2030. Industrial heat pumps are incentivized for their low-carbon attributes as well. The EU
plus the UK is the major demand and growth market for industrial heat pumps.
High European natural gas prices in 2022-2023 made heat pumps more competitive and
along with the urge to decarbonize, are keeping the market going and growing.
As in residential
heat pumps, the sources for the heat to be exchanged may be air, surface water,
groundwater, soil, or rock. External heating may be added where applicable. An
article in Thermal Engineering lists 12 types of industrial heat pumps, as described below.
Types of High-Temperature Industrial Heat Pumps
(>70 degrees C)
1.
Compression Heat Pumps:
These pumps use mechanical energy to compress a refrigerant, which then heats
up as it is compressed. Variants include air-source, water-source, and
ground-source compression heat pumps.
2.
Absorption Heat Pumps:
Utilizing a heat source, such as natural gas or solar energy, these pumps rely
on an absorption cycle involving a refrigerant and an absorbent fluid, commonly
used where waste heat recovery is viable.
3.
Exhaust Air Heat Pumps:
Specifically designed to recover heat from exhaust gases in industrial
settings, these pumps are effective in reducing energy consumption and
environmental impact.
4.
Steam Compression Heat Pumps:
These pumps elevate the pressure and temperature of steam, making it suitable
for processes like sterilization or heavy cleaning.
5.
Gas Compression Heat Pumps:
Similar to steam compression, these devices compress gases other than steam,
adapting the temperature and pressure to specific industrial needs.
6.
High-Temperature Heat Pumps:
Capable of reaching temperatures up to 150°C, these are used in processes
requiring significant heat, such as drying and curing operations.
7.
Cogeneration Heat Pumps:
These systems combine heat and power generation, utilizing the waste heat from
electricity production to enhance overall efficiency.
8.
Chemical Heat Pumps: These
use chemical reactions to absorb or release heat, providing energy savings and
environmental benefits.
9.
Desiccant Heat Pumps: Ideal
for operations requiring humidity control, these pumps combine moisture
absorption properties with heat pumping.
10.
Solar-Assisted Heat Pumps:
Incorporating solar energy to reduce electricity usage, these systems are both
sustainable and cost-effective for daytime industrial operations.
11.
Geothermal Heat Pumps:
Using the stable temperatures of the ground or water sources, geothermal pumps
are highly efficient for both heating and cooling purposes.
12.
Hybrid Heat Pumps:
Integrating features of different heat pump types to optimize performance and
efficiency according to specific application requirements.
Low and
medium-heat industrial heat pumps are considered to be mature technologies, but
high-temperature industrial heat pumps are not yet considered mature. The McKinsey & Company report lists five considerations of
industrial heat pumps worth considering, summarized below:
1. There is no one-size-fits-all solution for industrial and district heating – differences in parameters like temperature, capacity, physical size, and integration into existing equipment are common. There is often a need for modifications and customization. Design and installation training will be important to develop more expertise in modifying and customizing industrial heat pump applications. Heat pump original equipment manufacturers (OEMs) need a better understanding of use cases and end-users need a better understanding of the technology. Another consideration is that those who operate fossil fuel or biomass-powered district heating systems may not be competent in operating heat pump systems.
2. A high-performing industrial heat pump is
more than just a compressor – Heat pump performance is determined by the compressor, heat exchangers (condenser and evaporator), and control software.
Compressors control refrigerant flow rates and compression efficiency. Compressors
can be complex and typically account for 20-35 % of overall hardware CAPEX. While
compressors get the most attention, heat exchangers and control software can
also increase efficiency and ensure that coefficients of performance (COPs) are
up to standards. Smart controls can optimize performance and help with predictive
and preventive maintenance. Standardization and modularization can also help
the industry reduce costs.
3. The race is still on between natural and
synthetic refrigerants – The choice of refrigerant can vary depending on
project type, size, and where it is built. They explain:
“There are two groups of
refrigerants: hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs),
and natural refrigerants. Some OEMs focus on only one group of refrigerants,
whereas others have both groups in their portfolio (sometimes for historical
reasons). While HFCs and HCFCs have been widely used in the past, there is a
trend, especially in Europe, toward natural refrigerants because of (potential)
environmental regulation, such as the F-gas quota limiting the use of
fluorinated refrigerants with high global warming potentials (GWPs).”
Natural refrigerants include hydrocarbon
gas liquids (aka natural gas liquids) such as propane, isobutane, and
isopentane. These are flammable. They are applicable in many situations and have
a much lower GWP than any of the F-gases. They mention some other common refrigerants
and ongoing research:
“Ammonia, which is widely
used for refrigeration applications, is toxic, but it allows for very efficient
thermodynamic cycles with zero ozone depletion or global warming potential. CO2
typically requires a transcritical cycle with high pressures and is best suited
for applications where large temperature increases are needed. CO2 gains
attractiveness in refrigeration as well as heating applications because it is
nontoxic, nonflammable, and nonfluorinated. Water is an interesting refrigerant
for high-temperature applications (steam compression), but evaporation must be
run in vacuum for source temperatures below 100°C. Today, these and other
alternative refrigerants are being researched and subsidized.”
4. The most attractive use case combines heating
and cooling demand – Being the owner of a heat pump I can attest to this as
my electric use from A/C is very low. Combined heating and cooling apps can be useful
in the food and beverage industry and for combining different buildings and facilities
for shared systems. Heat pumps can be integrated with waste heat recovery and
transfer among different end-users. Heat pumps can be integrated with district
heating and with thermal energy storage, which can be used for power demand response.
5. OEMs, end users, and engineering,
procurement, and construction firms need to collaborate to create the best
solutions – OEMs need to develop standardization and modularization, which
requires deeper knowledge of each specific industry. They recommend “continued
R&D with an emphasis on design to value.” End-users and design engineers
should collaborate more, they say, especially on developing use cases. Engineering,
procurement, and construction (EPC) firms can leverage their industrial heat
pump installation expertise and their relationships with end users to help
develop optimized solutions. New sales models such as off-the-shelf solutions,
rentals, and support and maintenance agreements can be incorporated. In many
cases, heat pumps will be retrofitted, which often requires customized solutions
that this collaboration can facilitate. The goal of this collaborative approach
is better integration of design, manufacturing, installation, and end-use.
A 2016 paper
in Applied Energy discusses industrial heat pump technology and research in
China “including advances in refrigerants, multistage system, double-effect
absorption system, compression–absorption system, solar assisted system, and
chemical heat pump system.” The paper also gives some general information
about different industrial heat pump cycles.
“There are several heat pump cycles in industrial
applications. These cycles can be divided into the following categories: vapor
compression cycle (mechanical compression cycle), mechanical vapor
recompression cycle, thermal vapor recompression cycle, absorption cycle, and
chemical heat pump.”
Siemens Energy is
a major manufacturer of industrial heat pumps. They list the benefits of
industrial heat pumps:
More efficient than direct conversion of electric power
to heat
Simultaneous production of heat and cold due to thermal
action
CO2-free and free of emissions, when power from renewable
sources is used
Low levelized life-cycle cost of heat: Long term economic
solution with low CAPEX and OPEX
Easy to integrate in existing processes and applications
Proven, reliable technology: Regular heat pumps are
commonly available and attached to households. Large industrial heat pumps are
being up-scaled and continuously improved and optimised by us.
Waste heat can be re-used and sold for other purposes,
connecting different applications (enabling new business models)
Dynamic operation: Short ramp rates
Power grid stabilization: Peak shaving for excess power
generation to balance supply and demand, surplus power from renewable sources
can be converted into heat
In Europe in particular, the use of curtailed renewable
energy to generate thermal energy storage reserves and the development of waste
heat recovery and transfer technology is in development.
The
new river heat pump from MVV supplies climate-friendly heat from Rhine water to
around 3,500 households - One of the largest heat pumps of its kind in Europe.
Refrigerant Blending
In order to
utilize different temperatures for different industrial processes on the same
system, it was traditional to use a different heat pump for each process. The
new technology of blending refrigerants on the fly for different processes
offers a way to use the same heat pump for different temperature applications.
This solution has been developed by researchers from ETH Zurich and the Eastern
Switzerland University of Applied Sciences in Buchs as a way to make heat pumps
more flexible and to save money. The researchers note in their recent paper in
the International Journal of Refrigeration:
“Some industrial heat pump applications come with
challenges very different from residential heat pump applications, among them
very high heat sink temperatures, the generation of steam or overcoming large
temperature changes in the heat source and heat sink. For large temperature
changes in heat source and sink, zeotropic mixtures have been proposed because
of their glide which can match the temperature profile of the secondary fluids
given counterflow heat exchange arrangements and possibly improve the COP
significantly.”
Some of the mixtures analyzed in the past and present are
in the table below. In the second table below are the pure and blended
refrigerants tested in the study. They showed that the mass fraction of different
components, all other parameters being the same, affected COPs. COP is also affected
by temperature changes in the heat exchangers. According to TechXplore:
“The composition of the refrigerant blend can be
varied to cater to different applications. This is a key benefit for companies:
instead of having to redesign the entire heat pump whenever they need a
different temperature, they can simply modify the mixture, which is much
simpler and cheaper.”
“The mixture itself consists of a traditional
refrigerant and one further component. The temperature profile of the heat pump
is dictated by the ratio of these two ingredients.”
Thus, it seems likely that industrial heat pumps
utilizing refrigerant blends to increase flexibility and allow the pumps to be
used for multiple industrial processes simultaneously, will be a future trend
that will improve overall efficiency.
Case Study – Retrofitting an Industrial Cleaning Machine
with a Propane Refrigeration Circuit
New research from
Fraunhofer-Institut für Solare Energiesysteme ISE in Germany, provided by
TechXplore, shows that adding a propane refrigeration circuit to an industrial
cleaning machine can save considerable electricity, CO2 emissions, and water. Since
the two processes of the cleaning machine, cleaning and drying, are done at
different temperatures it provides an ideal situation for a heat pump to be
utilized for efficiency. The researchers designed a refrigerant system with
propane that was below the allowed maximum limit of 150 grams of propane due to
safety laws regarding flammability. TechXplore noted that the propane refrigerant
system “is also promising in other processes that operate in a similar
temperature range (50°C–70°C), such as large dishwashers in canteens.”
References:
Industrial
heat pumps: Five considerations for future growth. McKinsey & Company. March
19, 2024. Industrial heat pumps: Five
considerations for growth | McKinsey
Electrifying
industry with flexible heat pumps—a new approach may help companies generate
carbon-free process heat. Christoph Elhardt. Tech Xplore. June 12, 2024. Electrifying industry with flexible
heat pumps—a new approach may help companies generate carbon-free process heat
(msn.com)
Large-scale
industrial heat pumps: Proven high and low temperature industrial heat pumps
for up to 150°C and 70 MWth. Siemens Energy. Heat pumps (siemens-energy.com)
Think
big! Large heat pumps for climate-neutral district heating networks. Siemens
Energy. February 16, 2024. Large heat pumps for climate-neutral
district heating networks (siemens-energy.com)
A
comprehensive review on advances and applications of industrial heat pumps
based on the practices in China. Jing Zhang, Hong-Hu Zhang, Ya-Ling He,
Wen-Quan Tao. Applied Energy Volume 178. September 15, 2016, pages 800-825. A comprehensive review on advances
and applications of industrial heat pumps based on the practices in China -
ScienceDirect
12
Types of Industrial Heat Pumps for High-Temperature Applications. Thermal
Engineering. May 25, 2024. 12
Types of Industrial Heat Pumps for High-Temperature Applications
(thermal-engineering.org)
Heat
pump with propane refrigeration circuit developed for industrial applications. Claudia
Hanisch. Tech Xplore. June 2024. Heat pump with propane refrigeration
circuit developed for industrial applications (msn.com)
High-glide
refrigerant blends in high-temperature heat pumps: Part 1 – Coefficient of
performance. Leon P.M. Brendel, Silvan N. Bernal, Philip Widmaier, Dennis
Roskosch, Cordin Arpagaus, André Bardow, and Stefan S. Bertsch. International
Journal of Refrigeration. Volume 165. September 2024, Pages 84-96. High-glide
refrigerant blends in high-temperature heat pumps: Part 1 – Coefficient of
performance - ScienceDirect
No comments:
Post a Comment