Pump Model Research Articles

Advanced 2D Computational Fluid Dynamics Model of an External Gear Pump Considering Relief Grooves

The article presents an advanced two-dimensional (2D) computational fluid dynamics (CFD) model of an external gear pump which considers relief grooves. Relief grooves are limiting design features for the flow process of this type of pump, and their influence in existing studies is considered by a three-dimensional (3D) model only. The structural modification proposed by the authors is beyond the possibilities of real implementation, but it gives the possibility to precisely model the pump’s design features. In contrast to the existing studies (using 3D CFD), the proposed advanced 2D model requires significantly fewer computing resources. Numerical experiments were carried out using the 2D model at different pump operating modes depending on the rotation frequency (950–1450 min−1) and pressure load (5–150 bar). The numerical results were validated by a real-world experiment for the same pump operating modes using an existing laboratory experimental setup. An analysis of the CFD model and real experiment results was carried out by determining a quantitative index of match (FIT), which varies in the range of 97.93–99.82%. This proves the performance of the proposed CFD model, which can be further used as a part of more complex hydraulic systems models.

Multi-membranes-based pumping flow of nanofluids: Application in thermofluidic system

Microscale heat transfer plays a crucial role in various smart thermal devices such as microchannel heat sinks, micro heat pipes, and thermosyphons, as well as in bio microfluidics applications where biological fluids are being transported via natural pumping mechanisms. Inspired by the importance of microscale heat transfer, a biothermal-based pumping flow model integrating membrane-based pumping mechanism and nanofluids is developed mathematically. A Ghost-Valve model for membrane pumping is adopted based on Yasser’s model. Conservation principles for mass, momentum, energy, and nanoparticle volume fraction are considered for the mathematical formulation. The main objectives of this bio-thermo-physical model are to provide insights into pressure gradients, velocity distributions, volumetric flow rates, shear stress, streamlines, isotherms, nanoparticle volume fraction, Nusselt number, and Sherwood number under the effects of key parameters. Additionally, entropy generation analysis is presented with variation of thermal Grashof number, basic density Grashof number, Brinkmann number, and relative temperature on system performance. An analytical approach has been employed to derive the solutions under low Reynolds number approximation, and results are computationally analyzed using MATLAB code. Our findings highlight the effectiveness of membrane-based pumps in controlling microfluidic flow and heat transfer within microchannels and it is reported that velocity field enhances in magnitude with increasing the time phase lag parameter. This model will also present a benchmark for various future models to be developed for the nanofluids flow with various combinations of nanoparticles and base fluids through various flow regimes to be utilized for various purposes of the thermal systems/energy systems and offering valuable insights for optimizing thermal-based pumping systems in microscale applications.

Delivering biochemicals with precision using bioelectronic devices enhanced with feedback control.

Precision medicine endeavors to personalize treatments, considering individual variations in patient responses based on factors like genetic mutations, age, and diet. Integrating this approach dynamically, bioelectronics equipped with real-time sensing and intelligent actuation present a promising avenue. Devices such as ion pumps hold potential for precise therapeutic drug delivery, a pivotal aspect of effective precision medicine. However, implementing bioelectronic devices in precision medicine encounters formidable challenges. Variability in device performance due to fabrication inconsistencies and operational limitations, including voltage saturation, presents significant hurdles. To address this, closed-loop control with adaptive capabilities and explicit handling of saturation becomes imperative. Our research introduces an enhanced sliding mode controller capable of managing saturation, adept at satisfactory control actions amidst model uncertainties. To evaluate the controller's effectiveness, we conducted in silico experiments using an extended mathematical model of the proton pump. Subsequently, we compared the performance of our developed controller with classical Proportional Integral Derivative (PID) and machine learning (ML)-based controllers. Furthermore, in vitro experiments assessed the controller's efficacy using various reference signals for controlled Fluoxetine delivery. These experiments showcased consistent performance across diverse input signals, maintaining the current value near the reference with a relative error of less than 7% in all trials. Our findings underscore the potential of the developed controller to address challenges in bioelectronic device implementation, offering reliable precision in drug delivery strategies within the realm of precision medicine.

Effect of Structural Parameters on Output Characteristics of a Novel Self-Supplied Aviation Intelligent Pump

The aviation intelligent pump system is an effective solution to aircraft hydraulic systems’ inefficient power consumption and temperature increase. A self-supplied aviation intelligent pump (SAIP) has a high power-to-weight ratio and compact structure, making it the optimal choice for an intelligent pump. To analyze the output characteristics of a novel aviation intelligent pump, it is crucial to establish an accurate mathematical model that describes its dynamic characteristics. This can be achieved by analyzing the working principle and exploring the influence of critical parameters. The paper introduces the composition and working principle of a self-supplied electro-hydraulic servo variable displacement pump. It then establishes a mathematical model of the whole pump, with a detailed analysis and modeling of the critical variable mechanism and the swash plate assembly’s load moment. A simulation model was created to examine the impact of crucial structural parameters, such as the offset spring’s stiffness and control piston’s diameter, on the output characteristics of the intelligent pump. An experimental platform was also constructed, and the experimental results confirm the accuracy of the SAIP model presented in this paper. The investigation of the output characteristics fully reveals the dynamic performance of the SAIP. This provides the basis for the subsequent design of high-performance flow and pressure control strategies and aids in researching intelligent aircraft hydraulic systems.

A new approach to predict pump transient phenomena in Molten salt reactor Experiment (MSRE) by missing data identification and regeneration

Molten Salt Reactor Experiment (MSRE) is being extensively used for validating the computational tools for Molten Salt Reactors (MSRs). The pump transient tests were performed during the operation of MSRE to obtain the reactivity response to flow perturbation. The transient flow rate during this set of tests is required as input to predict the reactivity response. Since the primary loop of MSRE was not equipped with a flow rate meter, the transient flow rate, which is the crucial factor for the reactivity change in MSRE, is missing. Achieving an accurate simulation of the reactivity response to the MSRE pump transient tests necessitates a precise estimation of the transient flow rate.This paper endeavors to reconstruct the missing flow rate with the aim of offering a valuable input for simulating reactivity responses in the pump transient test series. In order to obtain an accurate transient flow rate, we employed a centrifugal pump transient model based on the affinity laws and solved the model for the MSRE secondary pump to validate the underlying assumptions of the model. In addition, we constructed the homologous pump head curves based on the water test data for the same purpose. The affinity law approximation is proved to be adequate in predicting the MSRE pump startup transient with the root-mean-square error (RMSE) in the normalized flow rate to be 0.03. On the other hand, for the MSRE pump coastdown transient, the preliminary results indicate that neither the affinity law approximation nor the homologous head curve is sufficient to provide acceptable predictions. To overcome this noticeable modeling deficit, we propose an innovative approach based on a straightforward data mining technique to regenerate the MSRE pump coastdown homologous relations using the measured data of the secondary pump. These relations are transferred to the primary pump and used to simultaneously solve for the impeller speed and the flow rate of the pump in the primary pump coastdown. With the new approach, the estimated RMSE in the normalized pump speed for the primary pump coastdown is reduced 0.0052. This excellent agreement validates the accurate calculations for the flow rate during the pump coastdown transient. We also performed an uncertainty analysis to quantify the confidence interval of the predicted quantities, which further justifies the robustness of the proposed approach.

Numerical modelling of earthquake sequences involving valving and pumping of fluids

SUMMARY Faults in the upper crust are sometimes thought to act as self-sealing valves, episodically releasing highly overpressured fluids trapped at greater depth during earthquakes. They are also often considered to be capable of actively pumping fluids into or out of faults in response to coseismic volumetric strain, thermal pressurization or other mechanisms. In this study, we investigate how these different types of behaviour (i.e. valve versus pump) are manifested in earthquakes. We do this using a 2-D plane strain model where frictional sliding on a thrust fault that is fed by a fluid source at its base is coupled to porous flow, thermal pressurization and strong variations in permeability. Our results show that thermal pressurization leads to dramatic dynamic weakening that produces earthquakes that propagate as slip pulses producing large stress drop, large slip and high slip velocities. On the other hand, valve-type behaviour typically produces smaller, less energetic earthquakes that commonly arrest before rupturing the entire fault. In some valve models, we observe complex compound ruptures and swarm activity, which is linked to the ascent of a propagating fluid pressure pulse driven by a large increase in permeability during sliding. Both pump and valve mechanisms can produce anomalously weak faults, though they are each associated with distinctly different fluid pressure and strength evolution over the seismic cycle and during rupture. Our models highlight the complex way in which fluids may interact with earthquakes, especially if valve and pump models coexist.

Circuit Model for HTS Flux Pump With Flux Conservation, Dynamic Resistance, and Flux Flow

Circuit Model for HTS Flux Pump With Flux Conservation, Dynamic Resistance, and Flux Flow

Research of the Meshing Performance of New Concave-convex Ball Teeth

Aiming at the limitations of the existing hydraulic pumps, a new type of bidirectional water-hydraulic internal ball gear pump using concave-convex ball teeth meshing to transfer power is proposed. In this paper, the principle of internal gear pump is utilized to establish the model of internal ball gear pump, and its mechanical properties and dynamic meshing characteristics are numerically investigated by using the finite element method. The results show that (a) the concave-convex ball gears run smoothly without any interference, and (b) increasing the number of gear rows can effectively reduce the maximum stress and meshing impact under a given load and speed. This study provides a basis for the development of high-performance ball gear pumps.

Experimental characterization and numerical modelling of an air to water CO2 heat pump under different outdoor and operating conditions for domestic hot water generation

This work assesses the influence of different outdoor and operating conditions on the performance of an air-to-water CO2 heat pump for domestic hot water (DHW) generation. For that purpose, an air to water CO2 heat pump with internal heat exchanger (IHX) was developed and characterized in an experimental campaign under well-controlled lab conditions. The system includes an in-house control system implemented to operate at the optimal gas cooler pressure. The heat pump and the control system are tested for DHW generation. The heat pump uses a finned-tubes heat exchanger as evaporator and plate heat exchangers as gas cooler and internal heat exchanger. The numerical model used a 1dimensional, cell by cell discretization method to characterize the performance of both, the gas-cooler and the evaporator under a wide range of values of their key variables. The IHX is also modelled with the same strategy. ARHI equations are considered to describe the compressor performance. The experimental data obtained are used to validate a numerical model of the heat pump under different air velocities, air temperatures and air humidity at the evaporator. The effectiveness of the control system proposed is experimentally confirmed during the experimental tests. Results show a good agreement between the numerical simulations and the experimental data what permits to validate the model and to assess the performance of the transcritical heat pump under different climate conditions.

Sex and tissue-specific downregulation of miR410-3p in a mouse model of cardiometabolic diseases

The brain Renin-Angiotensin System (RAS) plays a pivotal role in controlling cardiometabolic homeostasis, fluid balance, and other functions including inflammation. Previous studies have shown that more than a thousand microRNA (miRNA) families regulate RAS genes expression, and their dysregulation has been associated with HTN, cardiac ischemia, and aging. Recently, we observed that hypercaloric diet (HCD) programming resulted in differentially expressed miRNA in the hypothalamus of only the male progeny, including miR-410-3p which is thought to target angiotensin-II type 1 receptors (AT1R). Here, we aimed to investigate whether miR-410-3p regulate AT1R expression in a mouse model of cardiometabolic disease (CMD) exhibiting hypertension, diabetes and obesity. C57BI/6J mice (3-week-old, both sexes, n=10) were fed a HCD (D12492. 60 kcal% Fat, Research Diets, USA) while weight and fasting blood glucose levels were measured weekly to ensure the acquisition of metabolic syndrome. At 12 weeks of age, the mice were infused subcutaneously (osmotic pump model 1004, Alzet) with Ang-II (600 ng/kg/min/4 weeks). Gene expression of miR-410-3p (QRT-PCR) was reduced in the hypothalamus of CMD male mice (0.5 ±0.1 vs.1.0 ±0.1, p<0.05) but increased in females (1.6 ±0.4 vs.0.7 ±0.2, p<0.001), while both sexes showed a reduction in the heart (Males: 0.2 ±0.0 vs.1.7 ±0.3; Females: 0.23 ±0.0 vs. 3.2 ±0.3, p<0.01). AT1R protein expression (Capillary Western) was increased in the hypothalamus of CMD male (1.5 ±0.1 vs.1.0 ±0.2, p<0.05) mice but not in females (1.0 ±0.1 vs.1.2 ±0.1, P>0.05) while both sexes exhibited elevated levels in the heart (Males: 2.0 ±0.1 vs. 1.0 ±0.1; Females: 2.3 ±0.1 vs. 1.3 ±0.2, p<0.05). Binding specificity (luciferase assay) was further assessed between miR-410-3p and the 3’UTR of AT1R. Binding was decreased in presence of miR410-3p mimic (0.9 ±0.0 vs. 2.1 ±0.0; p<0.001) and enhanced by a miR410-3p inhibitor (2.5 ±0.1 vs. 2.1 ±0.0; p<0.01), confirming that AT1R is a direct target of miR410-3p. Together, our data suggest that in CMD downregulation of miR410-3p is associated with the upregulation of AT1R both in the hypothalamus and heart, notably in males. This positions miR410-3p as a possible new therapeutic strategy to control RAS overactivity in CMD. This work was supported in part by a research grant from the National Institutes of Health (HL163588). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Upregulation of miR-361-3p Is Associated With Impaired AT2 Receptor Expression in Cardiometabolic Diseases

Cardiometabolic homeostasis has been shown to be regulated by the brain Renin-Angiotensin System (RAS), including via epigenetic mechanisms. MicroRNA (miRNA) regulation is one of the most common mechanisms controlling the expression of RAS genes and has previously been implicated in hypertension, cardiac ischemia, and aging. Recently, we observed that hypercaloric diet (HCD) programming resulted in differentially expressed miRNA in the hypothalamus of only the male progeny, including miR-361-3p which is thought to target angiotensin-II type 2 receptors (AT2R). Here, we aimed to investigate whether miR-361-3p regulate AT2R expression in a mouse model of cardiometabolic disease (CMD) exhibiting hypertension, diabetes and obesity. C57BI/6J mice (3-week-old, both sexes, n=10) were fed a HCD (D12492. 60 kcal% Fat, Research Diets, USA) while weight and fasting blood glucose levels were measured weekly to ensure the acquisition of metabolic syndrome. At 12 weeks of age, the mice were infused subcutaneously (osmotic pump model 1004, Alzet) with Ang-II (600 ng/kg/min/4 weeks). BP, food intake and glycemia were recorded weekly while intraperitoneal glucose (GTT), insulin (ITT) tolerance tests and body composition (EchoMRI) were assessed at the end of the study. Gene expression of miR-361-3p (QRT-PCR) was increased in the hypothalamus of CMD male mice (2.0 ±0.5 vs.1.2 ±0.2, p<0.05) but not in females (2.7 ±0.8 vs.2.5 ±0.4, P>0.05). However, both sexes showed an increase in the heart (Males: 2.0 ±0.5 vs.1.0 ±0.3; Females: 1.6 ±0.4 vs. 0.8 ±0.2, p<0.05) which was associated with decreased AT2R cardiac expression (Capillary Western) in CMD male (0.9 ±0.0 vs.1.0 ±0.0, p<0.05) and females (0.1 ±0.0 vs.0.6 ±0.1, p<0.001). Together, our data suggest that in CMD, upregulation of miR-361-3p is associated with the decrease of AT2R in the heart, possibly contributing to impaired cardiac function in this model. This positions inhibitors of miR-361-3p as a possible new therapeutic strategy to control RAS overactivity in CMD. This work was supported in part by a research grant from the National Institutes of Health (HL163588). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Evaluation of Centrifugal Pump Availability Trends and Analysis

Centrifugal pumps are essential elements in industrial systems, facilitating fluid transfer and pressure generation across various applications. This study explores the vital task of evaluating centrifugal pump availability trends, focusing on three United Pumps crude delivery centrifugal pumps (P-90A, P-90B, and P-90C) over a span of seven years (2009-2015). With the use of derived equations and annual run-hours data from the facility's operations and maintenance database, the study ascertained the availability of the pumps. The findings and analysis showed that pumps P-90A and P-90B had significant decline in availability over the evaluation period (2009-2015), with P-90A finally failing in 2014. P-90C on the other hand, demonstrated relatively higher availability levels even though it was trending downward. The main cause of the decline in availability is attributed to the Original Equipment Manufacturers' decision to discontinue production of the pump model and its spares, which led to the substitution of locally made components for OEM parts. The study highlights the critical role, OEM support and its genuine spare parts play in optimising pump availability, reliability, and continuous operation—all of which prolong the pump's operating lifespan. It suggests improved methods, regular inspections, preventive maintenance, re-evaluating the quality of spare parts, and investigating replacement options. The study provides recommendations for improving pumping station performance and efficiency, based on empirical data and analysis, to industry stakeholders involved in crude oil delivery operations.

A Novel Method for Predicting the Behavior of a Sucker Rod Pumping Unit Based on the Polished Rod Velocity

Fault dynamometer cards are the basis of the diagnosis technique for sucker rod pumping systems. Predicting fault cards with a pumping condition model is an economical and effective method. The usual model is described by a mixed function of the pump displacement and pump load, and it is difficult to use in the prediction method based on the analytical solution of the sucker rod string wave equation. In this paper, a normal pumping condition model described by a function of polished rod velocity is proposed. For the analytical solution of the sucker rod wave equation, an iterative prediction algorithm with pumping condition models is proposed, its convergence is analyzed, and then it is validated by classical finite difference method simulated cards and measured surface dynamometer cards. The results show that the proposed algorithm is accurate. The algorithm has a maximum relative error of 0.10% for the classical method simulated card area and 1.45% for the measured card area. The research of this paper provides an effective scheme for the design, prediction, and fault diagnosis of a sucker rod pumping system with an analytical solution.

Divergent and Compensatory Effects of BMP2 and BMP4 on the VSMC Phenotype and BMP4's Role in Thoracic Aortic Aneurysm Development.

Vascular smooth muscle cells (VSMCs) play a key role in aortic aneurysm formation. Bone morphogenetic proteins (BMPs) have been implicated as important regulators of VSMC phenotype, and dysregulation of the BMP pathway has been shown to be associated with vascular diseases. The aim of this study was to investigate for the first time the effects of BMP-4 on the VSMC phenotype and to understand its role in the development of thoracic aortic aneurysms (TAAs). Using the angiotensin II (AngII) osmotic pump model in mice, aortas from mice with VSMC-specific BMP-4 deficiency showed changes similar to AngII-infused aortas, characterised by a loss of contractile markers, increased fibrosis, and activation of matrix metalloproteinase 9. When BMP-4 deficiency was combined with AngII infusion, there was a significantly higher rate of apoptosis and aortic dilatation. In vitro, VSMCs with mRNA silencing of BMP-4 displayed a dedifferentiated phenotype with activated canonical BMP signalling. In contrast, BMP-2-deficient VSMCs exhibited the opposite phenotype. The compensatory regulation between BMP-2 and BMP-4, with BMP-4 promoting the contractile phenotype, appeared to be independent of the canonical signalling pathway. Taken together, these results demonstrate the impact of VSMC-specific BMP-4 deficiency on TAA development.

Design and Simulation of the Biodiesel Process Plant for Sustainable Fuel Production

The biodiesel production process is extensively studied in the literature, focusing on mechanisms, modeling, and economic aspects, yet plant design and fluid flow losses remain underexplored areas. The study addressed this gap by designing a biodiesel production plant, analyzing flow losses, and developing a pipe network and suitable pump models. In this study, an integration of biodiesel production plant design and simulation of continuous production of Calophyllum inophyllum biodiesel was investigated. Biodiesel production encompasses complex stages that involve systematic planning and system design. The goal of the plant design is to reduce the losses that occur during the conversion process, which can reduce the capital cost of the plant. A few assumptions were made when selecting biodiesel plant materials, such as pipes, pumps, fittings, and bends. These assumptions were based on considerations of the biodiesel fluid properties and pressure requirements. On the other hand, Aspen Plus was used to simulate the biodiesel production process. Calophyllum inophyllum was considered oil as the biodiesel feedstock and was inputted to the Aspen Plus as triglyceride composition. The simulation was carried out with rigorous kinetic reactions using the Non-Random Two-Liquid (NRTL) method to predict the liquid equilibrium in the reactor. Results revealed that the designed steel pipe meets safety requirements with a bursting pressure of 49.68MPa, capable of withstanding the maximum pressure of 4 bar and turbulent flow conditions. Additionally, the selected pump satisfies the required head and flow rate, ensuring efficient fluid movement. Moreover, simulation results closely matched experimental data, and 88% of biodiesel yield was recorded.

A Water-to-Water Heat Pump Model with Experimental Validation

An experimental validation of a steady-state model for water-to-water heat pumps is conducted on a 10 kW test bench. The objective of the model is to predict the capacity and the required compressor power, based on the inlet conditions of the secondary fluids in the evaporator and condenser. Detailed manufacturer performance maps based on the AHRI 540-2020 standard are utilized to model the fixed-speed scroll compressor. A new semi-empirical model for the thermostatic expansion valve incorporates condensing temperature effects on superheating prediction. Sub-models for individual components, including detailed representations of the evaporator and condenser, are integrated into a global model, resulting in a set nonlinear equation solved using an equation solver with appropriate guess values. The validation of the model is conducted in an experimental test facility equipped with two precisely controlled secondary fluid loops. The heat pump is instrumented to measure condensation and evaporation pressures, the compressor discharge temperature, compressor power, superheating, and sub-cooling. The results are divided into three sub-sections: the first validates the complete heat pump model by comparing its power consumption and COPs in heating and cooling; the second compares the predicted and measured operational conditions; finally, it is shown how the model can be used to predict the non-operational conditions of the heat pump for specific scenarios.

Design and Characteristic Research on Variable Displacement Mechanism of Two-Dimensional (2D) Bivariable Pump

In a hydraulic system, a micro variable pump is required to be high pressure and high speed, and this work presents a new type of 2D bivariable pump structure in which the worm gear and worm mechanism are used to rotate the cylinder block to change the flow distribution state of the cylinder window and the piston groove to change the displacement of the 2D pump. The flow–pressure mathematical model of the 2D variable pump is established to analyze the relationship between pump displacement and the pump cylinder rotation angle and the effects of variable displacement on pump pressure characteristics, flow characteristics, and volume efficiency in Matlab. During the experiment, we tested the change in the corresponding pump output flow when the cylinder rotation angle is 0~12°, which verifies the correctness of the variable calculation model. The experimental results indicate that the volume efficiency and mechanical efficiency of the single-piston 2D pump are reduced to different degrees after variable displacement, the volume efficiency is reduced by approximately 3% at most, and the mechanical efficiency is reduced by approximately 5% at most.

267 Risk Factors Associated With Baclofen Pump Infection in Children Translated Into Health-Care Costs: A Retrospective Analysis From the Children's Hospital of Pittsburgh Experience From 2009-2020

INTRODUCTION: Intrathecal baclofen infusion is often used as a therapy for spasticity in children and adults, with pediatric cases more associated with infections. Infection leads to the need for pump explantation and is associated with a significantly increased hospitalization cost. METHODS: We retrospectively reviewed demographic, clinical, and economic data for children who underwent surgery for intrathecal baclofen pumps at a single institution from 2009-2020. Bivariable analyses (chi-squared tests) were conducted to compare differences in clinical characteristics between patients with surgical site infection and those without. Mann-Whitney tests were performed to compare total charges per patient between patients who had an infection versus those who did not. RESULTS: A total of 199 patients undergoing 442 surgeries were included. The cohort was 64% male and 84% Caucasian, with a mean age of 13.3 years. The most common indication for placement was cerebral palsy. Infection occurred in 28 patients (14% infection rate). The most common organisms were methicillin-resistant and methicillin-sensitive staph aureus. The pump model, access site, and the number of surgeons scrubbed were not associated with infection. Total hospital charges (for all surgeries) were significantly higher for patients with an infection versus those who did not ($231,762 vs. $187,028, p=0.0078), with an average charge increase of $44,734 associated with surgical site infection. CONCLUSIONS: In our single-center series, the most common indication for baclofen pump placement was cerebral palsy, with an infection rate of 14%, close to other rates reported in the literature. Total hospital charges were higher for patients with an associated surgical site infection than those without one.

Development of a digital heat pump model to analyze the system behavior in an intelligent network congestion management

Development of a digital heat pump model to analyze the system behavior in an intelligent network congestion management

Comparison of different strategies for operating a solar-assisted ground-source CO2 heat pump system for space and water heating

This study quantifies and compares operational strategies as applied on a solar-assisted ground-source trans-critical CO2 heat pump (CO2 SAGSHP) system for simultaneous space and water heating, optimized on an hourly basis over the course of a week. Four (4) boundary conditions, representing spring, summer, autumn, and winter, were considered. To enable the use of a dynamic model for optimization simulations, the use of a previously developed surrogate Artificial Neural Network (ANN) model of a Modelica CO2 heat pump model was evaluated for use in this study. The simulation results from the system model that applies the surrogate ANN model demonstrated strong alignment with those generated by the full Modelica model, yielding low root mean square errors and mean absolute percentage errors. Furthermore, it accelerated the speed of results generation for a single forward run by 6–15 times, depending on the boundary conditions. It can be inferred from the results of the optimization runs that when warm climate conditions dominate, implementation of the on/off operation with thermal energy storage (TES) should be prioritized, given that it could potentially yield greater operational cost benefits (12% to 58 % cost reduction) compared to hourly discharge pressure optimization (0.5 to 1.5 % cost reduction). Conversely, when colder seasons are longer, optimizing the CO2 heat pump's discharge pressure becomes more practical (6.5 % to 6.9 % cost reduction) than on/off operation, particularly when only a small TES is installed (1.2 % to 2.6 % cost reduction). The optimization of the mass flow rate of the supply side working fluid of a CO2 SAGSHP system exhibited minimal benefit, except notably in the summer where it generated an even better cost reduction than controlling the discharge pressure. This shows the practicality of this strategy for conditions where relatively high solar irradiation and relatively low heat demand are concurrently expected. In general, weekly reductions in operational costs were more substantial when both the discharge pressure and the on/off operation of the CO2 heat pump were concurrently optimized, especially when using a larger TES tank. Hence, both should be applied if there are no practical or cost limitations that restrict their implementation. While previous studies on CO2 heat pumps primarily emphasized efficiency optimization via discharge pressure control, this study shows that comparable or greater operational cost reductions can also be achieved from other strategies, depending on the boundary conditions.