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An effect of climate change is fewer cold days and less natural snow at lower elevations. This has spurred the interest in temperature independent snow (TIS) production, i.e., refrigeration technologies that can produce snow at ambient temperatures above zero. Commercially available TIS systems require a higher power consumption than conventional systems, i.e., snow lances and guns. Thus, to ensure that future snow-making sites are sustainable, it is necessary to develop solutions with a minimal environmental footprint. One possibility is to utilize surplus heat from industrial processes or from a district heating network to drive snow-making systems. Examples of heat driven refrigeration technologies fit for this purpose are absorption cooling and ejector cooling, both applying natural refrigerants. This paper evaluates a solution for heat driven ejector-based snow making systems: a vacuum ice slurry system using water (R718) as refrigerant. The required amount of driving heat and its required minimum temperature level largely depend on the ejector characteristics. Thus, to enable a proper evaluation, detailed numerical simulations of the ejector design and its efficiency were performed, at different temperature levels of driving heat and ambient temperatures. Results were used as input to estimate the overall performance, in terms of specific energy consumption (per m3 produced snow), compared to other TIS systems. The ejector-based system can be driven by low-grade heat (80 °C) and is shown to be highly efficient if cold cooling water (≤ 10°C) is available. Heat-driven snow production applying ejector and natural refrigerant

Natural refrigerant CO2 has become a viable choice for refrigeration units. The CO2 systems are working efficiently on land-based facilities, and their demand is increasing for offshore applications, e.g., cruise ships and fishing vessels, due to their environment-friendly nature and compactness. The investigated application of the CO2 system in this work is a single-stage system for air conditioning and a two-stage system for provision refrigeration at high heat rejection temperatures. The CO2 transcritical cycle allows operating in higher ambient temperatures and in a colder climate with significant heat recovery. However, the system efficiency decreases in higher ambient conditions due to the high-pressure ratio and expansion losses. Therefore, ejectors are implemented to boost the cycle efficiency at high heat rejection temperature conditions. The pressure exchanger (PX) device recently came up and claimed to be an option to recover expansion work in CO2 systems. PX is already in use for reverse osmosis (RO) desalination units to recover pressure work from the high pressure reject concentrate to low-pressure seawater. This work theoretically investigates the implementation of a CO2-PX for transcritical CO2 systems combined with ejectors and compressors. The energy efficiency of alternative system configurations is evaluated for various operating conditions. Simultaneous implementation of rotary pressure exchanger and ejectors for CO2 refrigeration system

This report delves into the challenge of implementing heat pumps, refrigeration systems and chillers (vapour compression systems) that use natural refrigerants, in the maritime sector. The first part gives a context, introducing the international organisations aim to reduce greenhouse gas emissions from the shipping industry, and defining the topic of refrigerant selection. The documents on safety requirements for vapour compression systems onboard, issued by the classification societies Lloyds Registers and DNV, are then summarised. The focus is on the implications for systems using natural refrigerants. It is found that a "case-to-case" evaluation of almost all these systems must be applied. In the last section the communication with the classification societies is summarised. The goal is to contribute to clearer and more standardised requirements on the use of natural refrigerants, to facilitate their safe implementation, environmental-friendly and long-term compliant maritime refrigerants.

More stringent international regulations on ship's emissions require a shift towards more climate friendly fuels, such as liquefied natural gas (LNG). On LNG-driven ships, the fuel is stored onboard at cryogenic temperature. The fuel must be vaporised before injected into the engine, implying a potential for cold recovery. Today, concepts are commercially available for utilising this surplus cold in conventional AC chiller system. This paper proposes an innovative concept where the LNG cold recovery system is integrated with a provision refrigeration system based on a CO2 booster unit and a cold thermal storage (CTES) due to the dynamic nature of loads and cold-recovery availability. The CTES is based on phase change materials (PCM) which, together with the choice of CO2 as refrigerant, ensures a compact system. The results show a potential for significant reduction in power consumption of the refrigeration systems and thereby contributing to reduced GHG emissions. Innovative refrigeration concept for passenger ships - combining CO2 refrigerant, cold recovery and cold storage

The objective of the CruiZE project is to develop innovative, integrated and environment-friendly concepts for supplying heating and cooling needs for the hotel facilities on board cruise ships. As in other sectors, there are non-technological barriers which must be addressed to pave the way for implementation of new technology. For example, increased knowledge is needed on the environmental indices that are applied by different stakeholders to assess a ship's environmental performance. In this memo such indices are reviewed, with a focus on cruise ships, and how the heating and cooling systems are addressed. This will form a basis for further work in CruiZE, aiming at suggesting recommendations on how to modify such indices, to encourage the implementation of innovative heating and cooling technologies. Included in the review are compulsory regulatory indices issued by IMO, voluntarily indices offered by classification societies, and indices applied to offer port fee reductions. The review shows that there is a need to adapt these indices to enable a more equitable assessment of new heating and cooling technologies

When assessing the carbon footprint of seafood from capture fisheries, the fuel use during fishing operation is the major contributor to overall greenhouse gas emissions. While the necessary shift towards low-carbon fuels and advancement in propulsion technology has commenced, also a more efficient use of energy is a key strategy for reduction of the emissions. Furthermore, leakage of high-GWP refrigerants contributes to emissions and a transition towards natural refrigerants (NH3, CO2) is essential. Introducing efficiency measures depends on knowledge of current performance. Due to the wide range of different fishing vessels with different on-board processing equipment and different modes of operation, the performance needs to be evaluated for each fleet segment before proper advise can be given. This paper presents energy measurement results from a research cruise conducted during autumn 2020 on a combined purse seiner/pelagic trawler. The vessel's refrigeration system was instrumented with sensors logging the electrical input to frequency converters (compressors and seawater pumps) and temperatures on the RSW side, while the vessels mode of operation and fuel consumption was logged on a regular basis during the cruise. The results provide insight on the vessel's energy flow, performance of the refrigeration system and fuel intensity of the fishing operation, which gives valuable input for design of efficiency measures.

The main objective of CoolFish is to increase energy efficiency of the utility systems (cooling, freezing and heating) onboard fishing vessels. To achieve a full potential of efficiency and environmental benefits the ship must be considered as an engineering system, i.e. also considering the propulsion system. Stricter environmental regulations and an increased awareness of energy use and emissions force the shipping sector to adapt new fuels and/or propulsion systems to replace the conventional mechanical diesel engines. This report provides an overview on such alternatives with focus on new-built and ordered Norwegian fishing vessels. The review shows a development towards diesel-electric or hybrid propulsion systems, often with hybrid power supply (e.g. batteries). Hybrid propulsion and hybrid power supply enables several operating modes, to match speed and auxiliary requirements, enabling flexible and fuel-efficient operation. However, it also implies challenges in relation to waste heat availability and sizing of heating and cooling equipment. Alternative fuels with high technical feasibility for the fishing sector include LNG/LBG and biodiesel for all fishing vessel types, and hydrogen fuel cells for coastal fishing ships. Battery implementations for partly electrified propulsion are considered highly feasible for the whole fishing sector.

A heat pump unit using CO2 as working fluid is designed to meet not only a part of the heating demand in the centralised kitchen at The Akshaya Patra Foundation, Bengaluru, India, but also the entire cooling demand to replace the existing HCFC units for AC. The proposed heat pump system generates hot water at ~90 oC which is stored in hot water storage tanks for use in the cooking cauldrons. Moreover, the existing space cooling systems are replaced by a centralised cooling system which circulates chilled water. In order to handle the fluctuation in cold and hot water demand, thermal storage systems are proposed. This concept offers substantial reductions in GHG emissions from the cooling system (approximately 60%). Furthermore, for the overall system (cooking process and space cooling) the reduction in energy demand, energy cost and GHG emissions are all above 30%.

This report provides an overview of standards, methods, certification schemes, tools, and previous studies related to the carbon footprint (CF) of seafood, both in general but especially related to fishing vessels and refrigeration systems. The aim is to give various perspectives on CF estimations for fisheries, as a basis for further work in CoolFish. A few standards are specifically developed for seafood products; the British PAS2050:2 and the Norwegian NS-9418. Sustainability certifications typically evaluate harvesting pressure, fishing practices and fisheries management. Even if energy use and emissions are often built into the assessment criteria, the CF is rarely specifically addressed. Online tools are available for CF estimations of seafood products, or parts of the product chain. Data for the fishery stage are based on conventional diesel propulsion, and the refrigeration system is only addressed by default values on refrigerant leakage. Previous studies on CF assessment of captured sea-food shows that the fishing vessel's fuel consumption is generally the dominant contributor. Emissions of synthetic refrigerants can also play an important role, as can air transportation. More disaggregated data on fuel use are required to evaluate on-board measures for CF reduction. Further work in CoolFish could contribute with estimations of fuel use for propulsion and refrigeration, for different fishing vessels and operational modes.

Water (R-718) is a safe and energy-efficient refrigerant. Mechanical vapour recompression (MVR), an open-loop heat pump using R718, can significantly reduce the energy consumption for steam-heated processes like drying, pasteurization, evaporation or distillation. However, the existing compression technology is not cost-efficient, especially in the capacity range from 500 kW to 4 MW. Therefore, a novel two-stage turbo-compressor system, developed for application in industrial superheated steam drying and based on mass-produced automotive turbocharger technology, was developed. Its performance was evaluated in a test facility, showing that it is possible to compress superheated steam from atmospheric pressure up to 3 bar, delivering 300 kW at 133°C, with a COP of 5.9, an isentropic efficiency of 74% and a Carnot efficiency of 48%. With an estimated investment cost of 150 €/kW installed heating capacity, the system clearly has the potential of being a cost-effective solution for heat recovery in steam-heated industrial processes. This chapter will not be available due to copyright restrictions (c) 2019 by International Institute of Refrigeration

Akshaya Patra Foundation is the world’s largest (not-for-profit) Mid-Day Meal Programme operating around 50 centralised kitchens supplying wholesome food to over 1.8 million children at more than 16,000 schools in 12 different states across India. In the project presented in this report, a heat pump using the natural refrigerant CO2 is proposed as an energy-efficient and climate-friendly concept for the centralised kitchen at Bengaluru. The CO2 heat pump does not only replace the HCFC units for space cooling, but also supplies hot water to the cooking process, reducing the steam boiler's fuel consumption. A cold and hot water storage is included to balance the mismatch in cooling and heating demand on a daily basis. The proposed concept offers substantial reductions in greenhouse gas (GHG) emissions from the cooling system (almost 60%). For the total system (cooking process and space cooling) the reduction in energy demand, energy cost and GHG emissions are all above 30%. This clearly shows the possibility for India to efficiently bypass the use of HFCs as temporary replacements for HCFCs, and by that avoiding significant GHG emissions and costly replacement processes. Suggestions for potential future improvements include a roof-top solar power system and a steam producing heat pump using natural refrigerants.

Cruiseskip-industrien møter for tiden økende krav når det kommer til utslipp, spesielt på lokal bane. Et eksempel på dette er at de norske myndighetene har bestemt at alle verdensarvfjorder, inkludert Geirangerfjorden, skal være nullutslippssoner innen 2026. Det er derfor interessant å studere muligheten for tradisjonelle cruise skip (les diesel-drevet) å tidvis operere med nullutslipp. Denne oppgaven vil i hovedsak fokusere på å oppnå dette når skipet ligger til havn, men løsningene som vil bli diskutert er like gyldige for å oppnå dette også for korte tider på havet. Det er da naturligvis nødvendig å kombinere løsningene med et elektrisk batteri. Et stort hinder som står i veien for at tradisjonelle cruiseskip kan operere med nul- lutslipp er å møte varmebehovet til skipet, ettersom dette under vanlig drift dekkes av restvarme fra dieselmotorene. Denne oppgaven vil ta for seg løsninger hvor man bruker termiske energilagre, i tillegg til varmepumper/elektriske varmtvannsberedere, til å møte skipets varmebehov. For å studere disse løsningene ble det laget en dynamisk modell av det termiske energisystemet på tradisjonelle cruiseskip i Dymola/Modelica. Simuleringene har vist svært gode resultater for å møte varmtvannsbehovene til skipet, spesielt når det termiske energilageret var basert på faseendringsmaterialer. Det var da mulig å møte alle varmtvannsbehovene i havn med et volum på kun 265 m3, gitt at varmeveklingsdesignet var basert på plater av typen ”pillow-plate”. En vanntank trengte et volum på 850 m3 for å møte disse behovene. Simuleringene ga derimot ikke spesielt bra resultater for vanndamp. Skipet som ble studert i simuleringene hadde for lite restvarme, i form av vanndamp, under cruising til å dekke behovene i havn med et energilager. Det ble derfor kjørt en simulering for å studere potensialet bak å bruke elektrisk varmtvannsbereder, som viste at varmtvannsberederen måtte levere en gjennomsnittlig effekt på omtrent 3.4 MW. Men, utfordringene knyttet til det å simulere vanndampen har skapt stor usikkerhet rundt disse resultatene. Cruise ships are currently facing increasing demands with respect to their emissions, particularly on the local scale. One example of this is that the Norwegian government has decided that the world heritage fjords, such as Geirangerfjorden, will be zero emission zones by 2026. It is therefore of interest to study the possibility for traditional cruise ships, read diesel-powered, to temporarily operate with zero emissions. This thesis will mainly focus on achieving this in port, but the solutions presented will be just as valid for short cruising, if one were to add a battery. A big problem standing in the way of temporary zero emission operation for cruise ships is how to cover the heat demands of the ship since this is, under normal operation, usually covered by utilizing the waste heat from the diesel generators. This thesis will study various solutions utilizing thermal energy storage, as well as heat pumps/electric boilers, to cover these heat demands. A dynamical model of the thermal energy system on traditional cruise ships was created, using Dymola/Modelica, to properly study these solutions. The simulations show very positive results for meeting the demands for high temper- ature water, particularly when using thermal energy storage based on phase change materials. For the pillow-plate based design a volume of merely 265 m3 could cover all heat demands in port! Doing this with a water tank required a volume of 850 m3. The simulations run does not, however, show great results for the steam. For the case ship used in the simulations there was too little waste heat available from steam to solve the heat demand using a thermal energy storage. Instead, an electric boiler was used, ant it was found that it needed to deliver an average power of 3.4 MW. However, the challenges of simulating the steam has given significant uncertainty to these results.

Energisystemer på passasjerskip har tradisjonelt vært basert på fossile brensler, som bidrar til store CO2-utslipp. Hovedfokuset har vært på å forbedre fremdriftssystemet på skip, mens fokus på å redusere energiforbruk i hotellsystemet har vært mangelfullt. Hotellsystemet på passasjerskip står for opptil 40 % av energiforbruket. For å effektivt redusere klimagassutslipp fra passasjerskip, er det derfor også viktig å ta hensyn til hotellsystemet. Denne masteroppgaven er en del av prosjektet CruiZE (Cruising towards Zero Emissions), som er et samarbeid mellom SINTEF Energi, NTNU, Carnival Corporation & plc, samt norske leverandører av skipsutstyr og designløsninger. Det overordnede målet til CruiZE er å redusere energiforbruket til hotellsystemer på passasjerskip gjennom innovative designløsninger. Målet med masteroppgaven er å analysere energiforbruket på passasjerskip og mulige energisparingsløsninger, ved hjelp av bygningssimuleringsverktøyet IDA ICE. Hotellsystemet til et cruiseskip ble modellert i IDA ICE, hovedsakelig basert på Color Lines skip Color Fantasy. Først ble viftekonvektorer med ubegrenset oppvarming og kjøling brukt i modellen. De første resultatene ble sammenlignet med energiforbruk på referanseskipene MS Birka Stockholm og et stort cruiseskip. Modellen ble deretter kalibrert ved å øke energiforbruket til tappevann og redusere ventilasjonsmengden i store kjøkken. Dette ga et totalt årlig energiforbruk på 19,2 MWh/passasjer for skipets hotellsystem. Energibehovet for fremdrift ble funnet å være 0,156 kWh/ALB-km. ALB (available lower berth) er tilgjengelige underkøyer, satt til to per lugar. Etter kalibrering ble det utført en analyse av forskjellige måter å dimensjonere viftekonvektorer. Det resulterende termiske miljøet var omtrent likt ved bruk av design værdata i varme- og kjølesimuleringer og ved bruk av maksimal varme- og kjøleeffekt fra en årssimulering. For de fleste soner bortsett fra vaskerommet, kan viftekonvektorene være betydelig underdimensjonert uten å påvirke det termiske miljøet. Dimensjonering av viftekonvektorene påvirket ikke skipets årlige energiforbruk i vesentlig grad. Skipets energiforsyningssystem, bestående av motorer og kjeler, ble tatt hensyn til gjennom etterbehandling av simuleringsdataene i MATLAB. To forskjellige brensler ble vurdert: marin gassolje (MGO) og flytende naturgass (LNG). En varmtvannstank på 150 m3 ble inkludert for å utnytte all ubrukt gjenvunnet varme fra motorer i MGO-skipet. Tanken ble også brukt til å redusere maksbehovet for kjeler fra 12,3 til 9,2 MW. Flere energisparingsscenarier ble undersøkt for å finne deres effekt på energiforbruket og maks. energibehov. Av de undersøkte løsningene ga varmegjenvinning i ventilasjonen, VAV (variable air volume) ventilasjon og en luft-til-vann-varmepumpe de største reduksjonene i brenselforbruk. På MGO-skipet ble kjelenes årlige brenselforbruk redusert med henholdsvis 30, 23 og 66 %. Den økonomiske lønnsomheten ble undersøkt for å finne løsningene som mest sannsynlig vil være egnet for implementering i et cruiseskip. Alle løsningene var mer lønnsomme på MGO-skipet enn på LNG-skipet, på grunn av at mer varme blir gjenvunnet fra LNG-motorer og at MGO er dyrere. Varmegjenvinning i ventilasjonen var tydelig lønnsomt på begge skip med en nåverdi over dobbelt så høy som investeringskostnadene. En luft-til-vann-varmepumpe var veldig lønnsom bare på MGO-skipet. Løsninger med periodevis redusert oppvarming hadde mindre reduksjoner i brenselforbruk, men de vil sannsynligvis være lønnsomme på grunn av lave investeringskostnader. VAV-ventilasjon var ikke lønnsomt nok til å anbefale. I videre arbeid kan modellen brukes til å undersøke effektiviteten til andre energisparingsløsninger. Dette kan inkludere varmepumper som bruker lavtemperatur vann om bord som varmekilde, dampproduserende varmepumper, og en kombinasjon av varmepumper og termisk energilagring. Energy systems on passenger ships have traditionally been based on fossil fuels, which contribute to large CO2 emissions. The main focus has been on improving the propulsion system on ships, while a focus on reducing the energy use in the hotel system has been lacking. Hotel systems on passenger ships account for up to 40% of the energy consumption. To efficiently reduce greenhouse gas emissions from passenger ships, it is therefore important to also consider the hotel system. This master's thesis is a part of the project CruiZE (Cruising towards Zero Emissions), which is a collaboration between SINTEF Energy Research, NTNU, Carnival Corporation & plc, as well as Norwegian suppliers of ship equipment and design solutions. The overarching goal of CruiZE is to reduce the energy use of hotel systems on passenger ships through innovative design solutions. The aim of this master's thesis is to analyse the energy use on passenger ships and possible energy saving solutions, using the building simulation tool IDA ICE. The hotel system of a cruise ship was modelled in IDA ICE, mainly based on Color Line's ship Color Fantasy. At first, fan coils with unlimited heating and cooling were used in the model. The initial results were compared to energy use on the reference ships MS Birka Stockholm and a large cruise ship. The model was then calibrated by increasing the demand for domestic hot water (DHW) and reducing the ventilation rate in large galleys. This gave a total annual energy consumption of 19.2 MWh/passenger for the ship's hotel system. The energy demand for propulsion was found to be 0.156 kWh/ALB-km. ALB is available lower berth, set to two per cabin. After calibration, an analysis of different ways to size fan coils was performed. The resulting thermal environment was similar when using design day data in heating and cooling simulations and when using the maximum heating and cooling power from a one year simulation. For most zones apart from the laundry room, the fan coils could be significantly undersized without affecting the thermal environment. The fan coil sizing did not significantly impact the ship's annual energy consumption. The ship's energy supply system, consisting of engines and boilers, was considered through post processing of the simulation data in MATLAB. Two different fuels were considered: marine gas oil (MGO) and liquefied natural gas (LNG). A hot water storage tank of size 150 m3 was included in order to utilise all unused recovered heat from engines in the MGO case. The tank was also used to reduce the peak demand for boilers from 12.3 to 9.2 MW. Several energy efficiency scenarios were investigated to find their effect on the energy consumption and peak energy demand. Of the solutions investigated, ventilation heat recovery, variable air volume (VAV) ventilation and an air-to-water heat pump gave the largest reductions in fuel consumption. On the MGO ship, the annual boiler fuel consumption was decreased by 30, 23 and 66%, respectively. The economic profitability was investigated to find the solutions most likely to be suitable for implementation in a cruise ship. All solutions were found to be more profitable on the MGO ship than on the LNG ship, due to more heat being recovered from LNG engines and MGO being more expensive. Ventilation heat recovery was clearly profitable on both ships with a net present value (NPV) more than twice as large as the investment costs. An air-to-water heat pump was very profitable only on the MGO ship. Solutions with heating setback had smaller reductions in fuel consumption, but they are likely to be profitable due to low investment costs. VAV ventilation was not profitable enough to recommend. In further work, the model could be used to investigate the effectiveness of other energy saving solutions. This could include heat pumps utilising low temperature water on board as a heat source, steam producing heat pumps, and a combination of heat pumps and thermal energy storage.

In a world with increased pressure on reducing fuel consumption and carbon dioxide emissions, the cruise industry is growing in size and impact. In this context, further effort is required for improving the energy efficiency of cruise ship energy systems. In this paper, we propose a generic method for modelling the power plant of an isolated system with mechanical, electric and thermal power demands and for the optimal load allocation of the different components that are able to fulfil the demand. The optimisation problem is presented in the form of a mixed integer linear programming (MINLP) problem, where the number of engines and/or boilers running is represented by the integer variables, while their respective load is represented by the non-integer variables. The individual components are modelled using a combination of first-principle models and polynomial regressions, thus making the system nonlinear. The proposed method is applied to the load-allocation problem of a cruise ship sailing in the Baltic Sea, and used to compare the existing power plant with a hybrid propulsion plant. The results show the benefits brought by using the proposing method, which allow estimating the performance of the hybrid system (for which the load allocation is a non-trivial problem) while also including the contribution of the heat demand. This allows showing that, based on a reference round voyage, up to 3% savings could be achieved by installing the proposed system, compared to the existing one, and that a NPV of 11kUSD could be achieved already 5years after the installation of the system.

The shipping industry is focusing more and more on reducing fuel consumption and greenhouse gas emissions. A non-negligible amount of fuel is consumed while ships are in port, waiting for loading or unloading, for heating up accommodation spaces and fuel tanks, while when at sea waste heat from engines exhaust is under-used because of low demand. In this paper we propose the use of thermal energy storage as a solution for the mismatch between heat availability and demand. A simplified system is proposed and the influence of design parameters (storage size, heat exchangers surface, secondary fluid mass flow rate, storage temperature) on the performance of the system is analyzed. The results of the application of a thermal energy storage system to a case study ship show that the installation of a storage tank of 1000 m3 could reduce the fuel consumption from the boilers by 80%, which would lead to yearly savings of 268,000 USD. This preliminary analysis shows that there is potential of both economic and environmental benefits from the application of thermal energy storage to merchant vessels.