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Heat Pumps - Science topic
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Questions related to Heat Pumps
Which one could be the good option to start with either air source heat pump or exhaust air heat pump to utilize waste heat from dryer exhaust?
Thank you!
I need to calculate the exit temperature of the heat source from the evaporator of a heat pump for a given situation. The heat source is a heat storage which provides source temperature of 40 °C. The flow and return temperature of the system is 70/50 °C, the heat demand is 100 kWh. The COP value of the heat pump is 3.0
The heat storage will be charged with the return (exit) flow from the evaporator. Thus, i need to know the temperature of it. What is the proper method to do this calculation ?
I would be grateful if someone could guide me how to get the input and output pressure in the compressor used in solar heat pumps? For example, in this article Annual comparative performance of direct expansion solar-assisted and
air-source heat pumps for residential water heating
unfortunately, i couldn't find any proper research papers about the influence of the flow-return temperature of the heating network (District heating) on the investment costs ( CAPEX ) of the heat generators such as CHP, Heat Pump and Biomass (Pellet,wood) boiler. I wanted to draw up a comparison between the heat generators in order to determine the most sensible variant for a given flow/return temperatures in terms of cost-effectiveness. I'm planning to establish a correlation between the temperatures and the capex.
I would really appreciate any help.
Best regards.
Can the installation of heat pumps powered by renewable energy sources significantly reduce the scale of the increase in the cost of generating heat and power or completely solve the energy crisis that exists in countries with a predominantly coal-based energy industry and thereby increase the level of energy independence and security?
In 2022, the scale of sales of heat pumps in Poland increased by approximately 100 per cent compared to the previous year. This was due to the energy crisis generated by the slowing down of the development of renewable and emission-free energy sources by the PIS party currently in power over the past eight years and the promotion of energy development based mainly on burning combustible fuels, mainly coal and lignite. As a result, three quarters of Poland's electricity generation and even more of its heat generation is still based on burning coal. As a result, when the price of fossil fuels rose sharply between 2021 and 2022, the cost of living for many citizens increased by several tens of percent. The solution to the problem of rising heating and energy costs was to install heat pumps powered by electricity from photovoltaic panels installed on the roof or next to the house, or other renewable energy sources. However, these other alternative renewable and emission-free energy sources are few and far between due to energy policy. In order to increase the energy savings of their homes, many citizens would like to insulate their homes by renovating and adding insulation to the facades of their buildings. It is estimated that over 4 million residential homes in Poland lack thermal insulation. However, this is unfortunately not possible due to the overly limited financial programmes of non-refundable subsidies with which such investment projects could be financed. Many citizens, despite the fact that they would like, for example, to power heat pumps with electricity from a wind turbine, a windmill erected close to their home, have not had this opportunity because in 2016 the PIS government blocked the development of wind energy in Poland by passing the so-called 10h Law. Similarly, in April 2022, a change in the regulation of billing for photovoltaic panels installed on the roof or next to a residential house by citizens prosumers of their own electricity made these installations unprofitable and the number of new installations of this kind fell by three quarters. When the development of wind power in Poland was blocked in 2016, coal imports increased strongly. In addition, nuclear power and other fully renewable energy sources were not developed. The result is a low level of independence and energy security for the country. Besides, the result is one of the lowest air quality and high levels of smog in cities during the heating season in international rankings. Unfortunately, despite the existence of new renewable energy technologies whose application on a larger scale could solve the above problems, the scale of development of governmental and self-governmental programmes of financial subsidies and support from the European Union is still too small. And it is too small because Poland has not met the so-called milestones set by the European Commission and is the only country in the EU which has not received financial subsidies under the National Reconstruction Programme. One of these milestones is the issue of unblocking the onshore wind energy development previously blocked in 2016. Currently, i.e. in Q1. 2023, a law is being processed to unblock this issue. However, the still ruling PIS party, as part of its support for the development of coal-fired power generation and its support for government-controlled, monopolistically operating energy and fuel companies of the state treasury, included in the aforementioned law provisions that in practice limit the development of onshore wind energy (a minimum distance of 700 m between a windmill and the nearest buildings) so that only a few per cent of the country's area can be covered by these windmills. This means that a small proportion of willing citizens will benefit from this, and it will benefit mainly and also to a limited extent the government-controlled, monopolistically operating energy state companies. Thus the circle of this travesty of energy, climate and environmental pseudo-politics is closing. In view of the above, technological solutions that could solve the above problems are already available, but the national pseudo-politics of energy, climate and environment causes that the development of renewable and emission-free sources of energy, improvement of energy security, reduction of the scale of the energy crisis, improvement of air quality in cities is still being slowed down, the goals of sustainable development are being ignored by the PIS government, and the green transformation of the economy, achieving zero-emission of the economy, building a sustainable economy in accordance with counteracting the progressive process of global warming is progressing much slower than it could be.
In view of the above, I address the following question to the esteemed community of scientists and researchers:
Can the installation of heat pumps powered by renewable energy sources significantly reduce the scale of the increase in the cost of generating heat and energy or completely solve the energy crisis existing in countries where the energy industry is mainly based on coal and thus increase the level of independence and energy security?
What do you think about this topic?
What is your opinion on this subject?
Please respond,
Please answer with reasons,
I invite you all to discuss,
Thank you very much,
Best wishes,
Dariusz Prokopowicz
I have modelled a heat pump and for a cooling capacity of 5 to 10kw, what would be the displacement volume, piston diameter and stroke length, number of cylinder in the compressor. I tried to research but I could not find, please do share
I am modeling a heat pump on the EES program and for the heat exchanger, I am using the NTU method to solve which requires iterations and I am unsure how to use it. If somebody explains it to me through an example then I will be thankful
To design a thermoacoustic heat pump to lift a temperature of 50-60 degree Celsius. what are the design parameters for it and what is the cost of the heat pump.
What are the interesting topics in the field of air conditioning right now? or future of air conditioning?
Are we stuck with the conventional methods of air conditioning? a research lead that could save energy and efficiency in the field of air conditioning?
Looking keenly for my next mission, which is a PhD in the future of air conditioning, heat pumps, refrigerant cycle improvement, advance air cooler maybe, AHUs, duct sizing, air simulation, CFDs! Is their a way out to top what is currently available? a sustainable sufficient energy efficient method?
I need to know the entire design procedure of the heat pump. How the compressor is selected based on the refrigerant and temperature? How each and every component of a heat pump is designed and the theoretical calculations behind them.
Which home heating systems based on green energy technologies should be developed in connection with the currently developing energy crisis and in the future also with the developing climate crisis?
If the currently developing energy crisis worsens significantly, how will you reduce your heating energy consumption and/or increase your household energy security in a situation where heating prices would increase by several tens of percent in the next heating season?
Nowadays, energy-saving solutions and systems are being developed due to rapidly rising fossil fuel prices. For example, solutions are being proposed for lowering the heating temperature in living spaces by a few percent when heating prices would still rise significantly. At present, many citizens are considering new investments in their household to increase energy security. Questions arise: maybe it is worthwhile in the near future, before the next heating season, to install new, renewable sources of heat and/or electricity at home, to insulate the house façade, etc.? Or are there already affordable new eco-innovations and green energy technologies that could be used now to increase energy savings? Besides, an energy crisis is currently developing and, in the long term, so will a climate crisis. When building a house now, it is important to take into account both the potential deepening of the energy crisis and the climate crisis in the future. In addition, the future correlation between the effects of both crises must be taken into account when planning heating systems and the electricity supply. Among the currently fast-growing green building heating technologies are the installation of heat pumps powered by electricity from photovoltaic panels installed on the roof of the house. In the future, the electricity supply for heat pumps may also come from domestic small-scale hydrogen power plants or nuclear fusion mini-reactors.
In view of the above, I address the following research question to the esteemed community of researchers and scientists:
Which home heating systems based on green energy technologies should be developed in view of the currently developing energy crisis and in the future also the developing climate crisis?
What is your opinion on this topic?
What is your opinion on this subject?
Please reply,
I invite you all to discuss,
Thank you very much,
Best regards,
Dariusz Prokopowicz
How do local government units in your country inspire citizens to save electricity and/or heat, conserve water sparingly, segregate waste, and other pro-environmental daily practices and actions?
How do local government units, including municipalities, as part of their pro-environmental and pro-climate policies, inspire citizens to save electricity and/or heat, conserve water sparingly, segregate waste and other pro-environmental, everyday practices and actions?
There have been many different crises since the beginning of the 21st century, and there is little indication that this would change in the years to come. The dotcom crisis at the turn of the 20th/XXI century, the global financial crisis of 2007-2009, the global recession of the 2020 economy triggered by interventionist measures carried out during the 1st wave of the SARS-CoV-2 coronavirus (Covid-19) pandemic, the overly lenient monetary policy carried out during the pandemic, the strong rise in inflation and the risk of stagflation in 2020, the currently developing energy crisis, the currently developing food crisis in some poorer countries, the already ongoing climate crisis that will intensify in the coming decades. As the levels of various risks increase, the scales and frequency of various crises increase, more and more public institutions, government agencies, NGOs but also local government units are taking various anti-crisis measures. Currently, the currently developing crises in many countries are: the economic downturn caused by high inflation; the energy crisis caused by high fuel and energy prices and low levels of energy self-sufficiency and underdevelopment of renewable energy sources; the climate crisis (and in some countries also the food crisis), the consequences of which include severe heat and droughts causing a decline in the production of agricultural crops, increased energy consumption and other negative effects. The climate crisis is likely to develop for many more years. In some countries, due to the low level of energy self-sufficiency, the low level of development of renewable and carbon-free energy sources, the scale of the currently developing energy crisis is greater and in the future, the negative effects of the climate crisis may also be more severe for nature and humans. Accordingly, local government units are also inspiring citizens to use water sparingly, save energy, segregate waste and other pro-environmental daily practices and actions. However, there are big differences in this regard when comparing environmental and pro-environmental policies and realistically carried out pro-environmental activities and green projects by individual local government units.
In view of the above, I address the following research question to the esteemed community of researchers and scientists:
How do local government units, including municipalities, within the framework of their pro-environmental and pro-climate policies, inspire citizens to save electricity and/or heat, conserve water, segregate waste and other pro-environmental daily practices and actions?
Please answer,
I invite everyone to join the discussion,
Thank you very much,
Best regards,
Dariusz Prokopowicz
If the home is heated and supplied with electricity from various renewable, carbon-free and possibly also non-renewable energy sources, to what extent can energy consumption savings be generated through the use of computerised, integrated management systems for various heating, lighting, white goods, white goods, white goods, etc. smart home systems?
If the house is heated and supplied with electricity from various renewable, emission-free and possibly also non-renewable energy sources, when on the one hand the energy for heating water can be generated from the sun, heating the house can be generated through heat pumps powered by photovoltaic panels, possibly from geothermal sources, etc., the energy for heating the house can be generated from the sun, the energy for heating the house can be generated through heat pumps powered by photovoltaic panels, possibly from geothermal sources, etc., etc. Electricity can be generated from home solar and/or wind power and any shortfall can be made up from external energy suppliers. However, when there is too little sunshine and no wind, the shortfall in electricity must be made up from other energy sources to power the heat pumps that heat the house. However, when there is an energy crisis and high energy prices from external suppliers, powering the heat pumps can become highly expensive. In such a situation, a modern, low-emission wood-burning cooker or an eco-friendly fireplace fuelled by biofuels can be run as an emergency. As the weather aura changes and the price of electricity from external suppliers (energy companies supplying electricity and/or system heat) changes, this type of complex, multi-source heating and electricity supply system for the home needs to be managed continuously. It may then be useful to use computerised, integrated systems to manage the various heating, lighting, white goods, white goods, etc. smart home. Computerised, integrated systems for the management of various heating appliances, lighting, white goods, consumer electronics, etc. smart home can make use of a specific generation of artificial intelligence technology and other Industry 4.0 technologies. Through such solutions for the improvement of smart, computerised, integrated home energy risk management systems, savings can be generated in terms of thermal and electrical energy consumption.
In view of the above, I address the following question to the esteemed community of researchers and scientists:
In a situation where the home is heated and supplied with electricity from various renewable, carbon-free and possibly also non-renewable energy sources, what energy consumption savings can be generated through the use of computerised, integrated management systems for various heating, lighting, household appliances, white goods, consumer electronics, etc. smart home?
What do you think about this subject?
Please respond,
Please answer with reasons,
I invite you all to discuss,
Thank you very much,
Regards,
Dariusz Prokopowicz
I am designing vertical geothermal heat exchangers, how can calculate the flow rate in u tubes per boreholes and also the total flow rate in the heat pump?
I used GHX tool (Excel) provided by Chaisson that use finite line source to calculate ground thermal resistance, did anyone have a description about the process of calculation ?
I have the electricity consumption profile of a reversible heat pump covering 1 year. The heat pump datasheet contains the SEER and HSPF.
I also know the thermostat setpoint for the building as well as the ambient temperature for each day in the electricity consumption profile.
I will like to know how to obtain the thermal profile considering that COP changes with temperature ?
I would like to know what are the necessary steps required to perform a geothermal potential assessment for the installation of a Ground Source heat pump destined for heating and cooling buildings. It basically tells you whether a site is suitable for geothermal heating or not.
Thanks in advance.
Energy coupling technologies connect two or more types of energy systems (energy vectors) to each other.
For instance, heat pump, electric/gas boiler, CHP/CCHP, fuel cell, etc., are energy coupling technologies.
In this context, what other technologies do you know?
The following work may be useful in this regard:
For industrial applications in ground-coupled heat pumps, a vertical U-tube, horizontal (straight and Slinkies) pipes are used. In the ground condensers and evaporators, metal tubes such as Copper are utilized. Is it practical from the manufacturing and maintenance point of view to implement fins (internal or external) to the buried tubes?
Thanks
Is there any research prospect to improve the efficiency of heat pumps through the different coupling modes of solar energy and air source heat pumps?
Solar heat pump is greatly affected by radiation intensity, resulting in unsustainable operation.
Dear All,
I am looking for international standard(s) to evaluate the rated capacity of thermal driven cyclic heat pump such as adsorption cycle for cooling or heating purposes. Do you have suggestions? Thanks!
Hi everyone. Does anyone know how to model an air to water reversible heat pump to feed the heated and cooled floor (radiant surface) in Designbuilder detailed HVAC? I can find air to water heat pump only for heating and it is not possible to make it reversible.
Thank you in advance.
I want to simulate the heat pump (air source) with unite storage thermal Tank but I get the following msg:
''350 : Unable to open the file associated with an
ASSIGNED logical unit number.
Please check the ASSIGN statement and make sure
that the file exists at the specified location''
and I want to,know also how can I creat a file
external if necessary
thank you
In my project, I am designing a heat pump system to replace the current one.
I have done some calculations and I have the refrigerant flow rate required for the cooling load to be achieved.
How do I calculate how much refrigerant (Kg) goes into the circuit?
I have the loop length of the circuit and the diameter of the tubing.
Any help and literature recommendations are appreciated.
Thank You
I was wondering if you could help me with a simulation as I am new to the programme, I am new to Abaqus and any help would be appreciated. I need to model heat transfer between the soil of temperature approximately 12 degrees and a concrete pile foundation with a pipe carrying water flowing through it of temperature of approximately 5 degrees. What's the best way to do this?
It is essentially the modelling of a geothermal heat pump but would like the readings of the drop in temperature in the soil.
Power-to-heat (P2H) shows how we can use renewables for heating. Power-to-heat technologies have been on the market for quite some time now, with heat pumps being the most important. However, they are only efficient at lower temperatures. Whenever very high temperatures are needed – for example, in the industry – electrode boilers are used.
So what do you think? Which technologies do you think will substitute the current fossil-fuel-based heaters in the future European energy system?
My model is a rectangular multi layered structure under which refrigerant flows through cylindrical pipes. A heat flux of 600W/m2 applied on panel and internal forced convection is used for refrigerant flow. Trying the phase change option from heat transfer in solids and fluids node but I am not getting any sollution.
Dear Sir/ Madam,
I need a manufacturer data of high temperature (70-80 Celcius) heat pump system for district heating network. I need a heat capacity table of an industrial heat pump to create quadratic equation of COP characterization.
Where can I find such heat capacity table/data for industrial heat pumps?
Kind regards
I am developing a regression model to predict the mass flow rate of a Direct Expansion Solar Assited CO2 heat pump (for a needle valve expansion device). The mass flow is based on the following equation:
m = Cd * A * [2 * rho * (Pi-Po)] ^ 0.5
For tests done in the sun, we have found a cd greater than 1. I expected this correction factor to be less than 1. But my experimental data, apparently show the opposite.
Good morning,
I am a student of the Mechanical Engineering Course of Udine University. Since I am at the last year of the course (fifth year), I am moving in order to collect information about the thesis. The theme I would like to deal with is the thermal management of the cabin and of the battery pack of an electric vehicle; my aim is to build a thermal model so as to be able to study the needs of cooling and heating of the vehicle and make considerations about possible ways of reducing energy consumptions of AC systems.
More specifically, in order to build an initial simple model of the heat pump system of the electric car, I should know the condensation temperature (or pressure) and the evaporation temperature (or pressure), in both cooling and heating mode, of the refrigerant used. I have made some research, and I have found the article "Performance evaluation of an integrated automotive air conditioning and heat pump system", that's why I am writing here. I have also found some other tables (here attached) which report reference numerical values.
Therefore, I have concluded that, in the cooling mode, the evaporation temperature of the refrigerant ranges from -2,5°C to 12,5°C and the condensation temperature of the refrigerant ranges from 50°C to 60°C. In the heating mode, instead, the evaporation temperature ranges from -4°C to 8°C, while the condensation temperature ranges from 45°C to 55°C. Do you think I can take these values as reference for my thesis, or could you gently provide me more precise numerical values? Thank you.
Best regards
Alessandro Fabiani
Since the instantaneous values of the compressor power requirement, pressure and temperature values at various locations of the circuit, and mass flow rate are highly fluctuating during the operation of VFD compressor-based heat pump system, what may be the better method to perform the energy and exergy analysis. Analysis based on the average values is giving some unbecoming results.
It is well known the impossibility of building a Perpetual Motion machine of any kind, but I want to talk about the following issue ...
the idea of building a perpetual motion machine using the Thermoelectric Effect (be the Thomson Effect, the Seebeck Effect or the Peltier Effect) is very tempting , since ideally the Thomson Effect and the combination of the Seebeck and Peltier Effect can be thought as a ideal reversible thermodynamic cycles ...
So I'v been thinking for a time now. How can we explain the impossibilities of building such perpetual motion devices; such a free energy running Thermoelectric Generator, a Heat Pump or Refrigerator.
I have been thinking such the irreversibilities should be in the electron/holes transport, as well as Phonon transport, sure these particles should create new amount of Entropy
Can anyone explain this in a coneptual and descriptive way , at a fundamental level (i.e.
Hi,
I'm modeling a heat pump using ammonia as the primary refrigerant and I'm evaluating the UA values of of the evaporator and condenser. I'm trying to find a reliable source of UA values for them, preferably a range looking at different type of HX (flooded, plate etc.) to use as a comparison.
Thanks in advance,
Matt James
I am working on heat pump assisted reactive distillation column. Trying to develop aspen plus model of vapor re-compression in reactive distillation column. the process includes three recycle streams ( one from separation column, one reflux stream and one reboil stream). I have used direct substitution method to converge the flowsheet. All blocks converge to desired results. But simulation ends with the error "solver block didn't converge in 100 iterations" and " solver block didn't converge normally in the final pass." increasing the no of iterations have no effect as depicted in convergence history chart. chart becomes linear. Not able to solve this error despite trying number of options. If anyone can help with this, it would be a great favor.
There are are a large number of emerging areas for uses of copper.These include e- vehicles,renewable energy sector,in starter and rotors of giant turbines ,high-efficiency thermal heat pumps,solar panels,hospitals,aquaculture etc.Copper demand growth opportunities are high
Hi all
I have data (e.g. T(out), operating hours and output power of the compressor, length of borehole) from a lot of Ground Source Heat Pumps. Can they be used to calculate subsurface temperatures? If yes, how? And do you have any idea how accurate these calculations are? Are we talking about errors in the range of < 1 °C or several degrees?
Thank you very much for your help!
Daniela
In order to integrate the geothermal as the primary source into the DH system, is it possible to only use heat exchanger to exchange the heat geothermal fluid in the separated loop or heat pump is the only option for this purpose?
Needed in the determination of the COP of the heat pump unit base on the ratio of useful thermal output and the electrical input
Hi
How can I calculate run fraction (Fc) based on bin method in ground source heat pump?
My question is about the simulation of an internally heat integrated distillation column (HIDiC) by using as software ASPEN PLUS. My main question is related how to calculate the exact amount of heat that can be exchanged in each stage between the rectifier and the stripper?
Thank you in advance!
If a bivalent heat pump unit serving a water-based circuit (that heats and cools an office) is working between evaporating at 5°C and condensing at 45°C, from a refrigerant condition point of view, how quickly can this unit be turned off?
The reason behind the question is building-grid interoperability when at times of grid congestion heat pumps can be turned off. I am wondering if the refrigerant operates between the temperature points outlined above, it might be necessary to run the heat pump for few seconds to allow the refrigerant to settle or move back from a super critical state (?) where otherwise and with a sudden shut-down the heat pump might be damaged.
Any advice or source of info would be great.
With solar heating systems characterised by their relative low flow and high head, I was wondering what the state of the art is with regard to solar application specific circulation pumps? It seems that many systems employ circulation pumps that run at extremely low inefficiencies.
As my experience with circulation pumps is limited, I would greatly appreciate any comments related to this query.
I am eager to know if it is logical enough from the Heat Pump point of view to switch it e.g. 80-100 times a day? How does it affect the life-cycle of the Heat-Pump? it would be really helpful if someone can share their practical feasibility insights on this. I am an electrical engineer and I have no expertise on the Heat-Pump operation. Literature suggests this control of switching, but I want to know whether it is really practical to do so.
What type of heat pump is the best choice to recover thermal energy from a small sewage water treatment unit?
“best" means compact with minimum power requirement.
Any suggested literature for thermo-economic analysis of heat pumps, particularly for low temp (sub-zero) applications.
Hi
I need Equations for Compute the geothermal system components?
Heat pump
heat exchanger
Borehole length
Design flow rate
Thanks
In performing transient simulations with ansys fluent (Workbench),The ansys file that is
created is huge (148 GB),and I have 27 case to simulate.
I am looking for any way to reduce the size of the results file.
Observations:
- In all cases ,I am interesting just for the inlet and outlet of fluid temperature and it's velocity.
- In all cases I have to simulate 93 days ,and all days contain the first 11 hours (I want to record it results ) and the last 13 hours(I am not interesting to record it).
I simulated ground coupled to heat exchanger with Ansys fluent and I want to calculate the mean thermal energy (KWh) transferred to the heat exchanger from the soil.
We are talking about dumping heat from 4 peltier element combined connected parallel to a 12V supply having ratting of 100 watt approx each.
I am trying to simulate a specific type of an Absorption machine under Trnsys, the machine is a Yazaki 17.6 kWcool.
My question is how can I create a parametric file of the Type 107 to meet the performance of my AB machine ?
I plan to start working on paper for Geothermics journal very soon where I will present more precise method of determining thermal conductivity by analyzing fall-off period after "classical" TRT time of min 48-72hr or longer. I have own sets of data which I measured on inclined coaxial heat exchanger (2*50m breholes drilled at 65° angle and equiped with coaxial probes 63/32 connected in series to achieve 100m in length). Data is 72hr TRT time and then equalt time recording fall off period with 3 different power supply. Since there is always power deviation during TRT (commonly due to day/night voltage fluctuations using public electricity grid) results of thermal conductivity always carry certain error in analysis. By analyzing fall-off period where there is stable decline in temperature could lead to overall more precise result in thermal conductivity, as prime factor in determining borehole grid size.
So, if anyone has some own TRT data gathered on BHE (preferably on 100m depth but not limited to) would be good to connect as possible co-authors and present measurements from different locations and geological setting.
Hi.
I want to know how air temperature can effect on air source heat pump operation ?
How we can illustrate it on heat pump T_S diagram?
Thank you so much.
what is the design pressures for condenser and evaporater in heat pump for a home?
I would like to know your practical experience about Open Loop GWHP (Ground Water Heat Pump) in confined aquifer. In my case I have 1 extraction well and 1 reinjection well. The problem is the rapid worsening of absorbability of reinjection well (from 15 l/sec to 3 l/sec in 12 months).
Thank you
The PCM whose latent heat of fusion is more and must have high cyclicity.
Hello Friends,
My pump flow capacity is 50 LPH and head requirement is 3.5 m.my pressure range is between 5 mm of hg to 70 mm of hg.My solution density is about 1600-1800 kg/m3.I have tried diaphragm pump,submersible pump ,magnetic rotor pump but all these pump didnt work properly.Is there any pump available in market that is suitable to my requirement?
The Laval Nozzle has been designed for given inlet and outlet pressure, so the throat is after certain convergent portions. Let's say however that the pressure inlet is changed from the design pressure, what will be it's effect on nozzle's performance? Will the flow adjust itself and get the lowest diameter at throat or will it mess up due to Mach no lower than 1 at the divergent portion inlet? Would the divergent portion act as a diffuser?
I am using the commercial library TIL to construct a Heat Pump cycle in DYMOLA. When integrating the components to form a closed cycle it fails to start (fails to reduce the DAE index). However when testing the components separately shows no such error. Can anyone help me to know the probable reason for such an error and suggest any method to overcome it.
Thanks in advance :)
The problem is to match the pinch point conditions at the absorber and the desorber of the LiBr-water absorption chiller, and also to evaluate the needed/evaluated concentrations of the LiBr in the LiBr-water solution.
It should be a heat pump model to heat air to about 65 degrees and the evaporator side may be used as an air dehumidifier. I need the correlations for different components of a basic HP so that I can convert it into Modelica code.
I want to calculate the experimental uncertainty for a geothermal heat pump as the reviewer suggestion of my paper?
Does anybody know how to configure Type 917 for a single zone building? I've been trying the example in the TRNSYS 17, however, I still couldn't tweak the performance of the Type 917 AWHP? Does anyone have experience using it?
I am working on ASPEN simulation for an OSN membrane which requires pressure to be set at 30bars but my exit stream from the pump is giving a very high temperature at the same pressure and low discharge flow rate
The sun is delivering a large amount of heat.
Buildings with large windows are able to collect this. Normally architects avoid overheating of building rooms by the sun. Otherwise there is the chance to use this heat and cool the rooms by air/water heat pumps. The stored heat can be used for warm water supply or to heat the rooms at the evening/night when outside temperatures go down.
For calculating the heat amount of the sun I need information about the volume of the sun input in dependence of the windows areas / building construction / region / seasons /....
Can anybody help?
With best regards
Michael
The notion of cascading for heat pump systems have been well developed to address efficiency drop in cold climates. Do you think it (cascading) also would help to enhance COP of system even for not critical working conditions?
I have read many articles about this topic. I wanted to hear some expert opinion about it. In my case. I'm interested in the flows of matter and energy coming in and out from the pump to the two different environments, and are not interested in the various internal losses and destruction of exergy.
There are good methods for modeling of water to water, Water to Air and Air to Air Heat pump, like parameter estimation and equation fit, but I couldn't find any method for modeling this Air To Water Heat Pump.