Stranica: 1/1.
Klima sa solarnom podrškom
Napisan post: 14 Avg 2015, 15:31
napisao vidovicb
Drage kolege,
prvi put se susrećem sa ovim sistemom pa me interesuje vaše mišljenje o prednostima i nedostatcima korišćenja solarne energije za podršku klima uređaju. Da li se ovo može naknadno dograditi? Da li je neko od vas imao iskustva sa ovim?
http://www.machine-history.com/Solar%20 ... nditioning
http://solarandmorehq.com/inverters/sol ... onditioner
http://www.alibaba.com/product-detail/s ... 41205.html
Re: Klima sa solarnom podrškom
Napisan post: 14 Avg 2015, 20:49
napisao nike
Brzi ti ide vako: Bezzzzee
Ali, pripazi na moje čelo. Nisan ti ja mjerodavan za te stvari! Samo mišljenje!

Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 12:36
napisao Soko
Nesto mi se ovde ne slaze. OK, u rezimu greajanja mogu da razumem ulogu sol. kolektora.
Medjutim, nikako mi ne ide da mu nadjem ulogu u rezimu hladjenja (a da to nije apsorpcioni sistem - sto nije).
Na ovim linkovima se polazi od tvrdnje kako kompresor koristi el. energiju da ugreje gas i kako dodatnim grejanjem tog gasa ovaj kolektor pomaze efikasnijem radu.
Koliko su mene naucili, najveci deo toplotne energije tog gasa potice od absorbovane energije na isparivackoj strani (iz hladjenog prostora).
Jedan deo toplote je od potrosene el. energije za rad kompresora, ostalo moze da se zanemari iako postoji.
Sad, kako ce dodatno dodavanje toplotne nergije u freon pomoci u radu? To je dodatna energija koju vaz. kondenzator mora da odstrani iz freona kako bi isti kondenzovao.
Moguce da nesto previdjam. Ako neko razume kako sol. kolektor pomaze hladjenje, molim da nam objasni.
Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 13:11
napisao fanzo
Kako je pitanje postavljeno na dvosmislen način i ja se pitam isto
Jedino može zimi da posluži za grejanje ako ima malo sunca.
Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 13:36
napisao nike
A hybrid solar air conditioning system uses a highly efficient vacuum tube collector filled with an organic liquid product. The collector heats the organic substance to over 350 degrees using the power of the sun to superheat the refrigerant above what the compressor would be able to heat it with electricity. The resulting efficiency derived from the solar collector allows for the refrigerant to work more efficiently with no additional moving parts or motors. This increases the ability of the gas to change back into a liquid much quicker and dramatically reduces the energy requirement of the compressor. The gas now condenses back into saturated gas in the first third of the condensing coil not the final third. Therefore by the time the refrigerant reaches the expansion devise in the inside coil, it is already almost a liquid. This allows the near liquid refrigerant to be more efficient at absorbing heat, making it 5-6 degrees cooler in the inside coil, delivering colder, drier air to the building. Refrigerant Type - 407c or 410
Koliko ja razumijem Engleski, navodno je stvar u većem pregrijanju plina nego što bi bilo pregrijanje u samom kompresoru koje je zbroj pregrijanja na usisu i pregrijanja od topline mehaničkog rada kompresora. Tu se u kolektoru dodaje još topline i plin se još više pregrijava a onda se NAVODNO, zbog veće temperaturne razlike plina od okolnog zraka taj isti plin bolje kondenzira u kondenzatoru tj. kondenzira se već u prvoj trećini kondenzatora pa imamo veće pothlađenje tekućine nego da nema tog kolektora. Ako je veće pothlađenje dobije se nešto na kapacitetu. Obično za 1 K pothlađenja računa se 2% kapaciteta više.
Kod: Označi sve
http://www.achrnews.com/articles/124391-btu-buddy-126-gaining-efficiency-with-subcooling
Meni ovo gore sa solarom kod hlađenja baš i ne drži vodu! Druga je priča kod grijanja!
Kod: Označi sve
https://www.youtube.com/watch?v=O9RQ0wsOtWo
Komentar jednog skeptika poput mene:
Don't need first stage when second stage is preempted by third stage.
Unless second stage preempts first stage first, before third stage stages a preemptive stage.
Got it!
Mene samo zanima kako to dodavanje topline prije kondenzacije ne podiže tlak i time kompresijski omjer i potrošnju kompresora. Dok mi to netko ne objasni za mene je ovo najobičniji šit!
Ovde je neko logično objašnjenje (Charless Law) ali mene još uvijek muči kompresijski omjer:
I am not a thermodynamics engineer, but I do have a degree in Civil engineering and remember my Gas Laws (Boyle's Law and Charles's Law). I don't know what you guys are missing, this appears to be simple Charles's Law applied differently. We already agree that the pump adds energy by increasing the pressure without increasing the volume, the temperature then rises. This is supplemented by the solar collectors which do the exact same thing, add energy, but instead of using electricity to drive a pump it is instead directly heated to 200C by the solar collectors which will also increase the pressure further. It matters not which way up the solar collectors are mounted as the fluid is still being circulated by the pump. The Gas laws state that where the volume remains the same and you increase the pressure, there is an associated rise in temperature (work done or energy added by the compressor converting electrical energy into heat energy) The solar collectors perform the same principle of efficiently converting solar radiation energy into a significant rise in temperature and pressure, except the heat/radiation energy provided by the sun is FREE. The same effect could be carried out by a second stage pump but it would waste lots of electricity and become uneconomic to run.
The superheated fluid coming out of the solar collector is now at a much higher temperature than ambient air and therefore can dump its heat energy by passing it through the fan unit WHILE MAINTAINING PRESSURE. Do you understand that heat energy at 200C is more efficiently TRANSFERRED to the ambient. So if the ambient is 50C (common in the Middle East) you can more easily transfer heat energy from a fluid at 200C than you can if it was only 100C. The temperature difference in the first case being 150C and in the second case only 50C
Now it is back to Charles's Law in reverse. The fluid/gas is now allowed to lose pressure in the indoor unit resulting in a proportionate drop in temperature of the gas. As more heat energy has been transferred to the ambient outdoors, there is less heat energy in the indoor unit fluid and the indoor unit now absorbs the heat energy from the indoor ambient air.
It is all down to the fact that free solar energy was used to super heat the fluid resulting in an increased pressure. This higher heat in the fluid makes it much easier to transfer the waste heat to the ambient outside air. The energy used to superheat the fluid came from a free source, the sun. These vacuum tubes are just ridiculously efficient at extracting the suns energy to heat fluids passing in the envelope of the vacuum insulator. I don't know how it became patentable to add 2 existing technologies together and make 1.
Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 13:55
napisao Soko
U teoriji dobro zvuci, malčice je drukčije u praksi.
Istina je, dobiće se veća temperatura gasa i veći deltaT na vaz. kondenzatoru. Samo zaboravljaju da kažu da sada u tom gasu ima dodatnih xx kilovata toplote koje treba predati okolnom vazduhu kroz isti taj vaz. kondenzator pa tu nestane sav dobitak ako ne i više od toga. Po meni, veća je ušteda staviti veći vaz. kondenzator.
Isto tako, zaboravljaju da kažu da to dodatno grejanje gasa podiže i pritisak na potisnoj strani koji kompresor mora da savlada a to ne ide samo od sebe.
edit. Nemoj da edituješ poruke dok neko piše odgovor na njih

Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 14:06
napisao nike
Kako ti prijatelju misliš da ja znam da ti pišeš odgovor?
Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 14:24
napisao nike
Evo tu i pojašnjenja koje opravdava i moje i tvoje sumnje:
It is a lie. A total FAIL But looking at these guys, they may actually believe in what they are doing, someone put them up to this and they don't look smart enough to figure it out. They run the first stage (or speed) of a two speed compressor because they have to compress the low pressure low temperature refrigerant vapor from the suction side of the evaporator coil to split the system between high and low pressure through the compressor. The output of the compressor is a high temperature high pressure vapor, and it has a certain VELOCITY of refrigerant provided by the compressor to push refrigerant through the system. They claim that by further HEATING ONLY of the high temperature high pressure vapor from the compressor, they are doing the same work that the second stage (or speed) of the compressor would have provided. But heating the vapor does not provide any additional velocity to the refrigerant, it simply heats it further, causing higher head pressure and higher compression ratio across the compressor, which draws more amps on the compressor motor (not good). Because it is a two speed condenser and they are running the compressor at half speed, the condenser coil still has the capacity to cool the vapor below the saturation temperature and condense it to a liquid, so their AC still works, they still get cold air from the evaporator coil inside the building, but it is the same (or slightly less) BTU capacity that they already had from just running the first stage of the compressor. It does not increase the BTU capacity to the same level as it would be if the compressor was running in high speed. And it does not increase the SEER or EER ratio, instead it will slightly reduce the SEER. This is like holding your acetylene torch on the output line of the compressor and expecting it to be more efficient. It will further heat the refrigerant which will create a higher pressure, but there is nothing to create a higher velocity of refrigerant through the system. Just heating refrigerant does not replace a compressor, there is no additional movement of the refrigerant through the system. If it were true, you wouldn't need a compressor at all, but obviously that doesn't work.
To increase the SEER of the system, you want to further cool the refrigerant temperature leaving the condenser, and also increase the temperature of the vapor leaving the evaporator coil, because that will reduce the compression ratio on the compressor, and that will take less amps to run the compressor. So higher SEER system will have a lower delta-T temperature drop across the evaporator coil. For the condenser, if it is 70 degrees outside, then the subcooled refrigerant leaving the condenser will be about 10 degrees higher than that, so 80 degrees. Now when the outside temperature reaches 110 degrees, the refrigerant leaving the condenser will be 120 degrees, making higher head pressure causing a higher compression ratio across the compressor, requiring more amps to compress the vapor. To prove it, put an amp meter on the compressor on a hot day, then spray cold water on the condenser coils and drop the refrigerant temperature leaving the condenser back down to 80 degrees, and watch the amp load on the compressor drop. That is why high SEER condensers are so huge, they have more surface area so that they can cool the refrigerant more and reduce head pressure. And luckily for these guys, the two speed condenser they are using it is big enough to remove the heat added by their solar heater. But an air condenser can never cool the refrigerant below the outside ambient temperature, just get closer to it. Your AC system looses about 25% of its capacity as the air temperature outside heats up over 110 degrees on a hot day. A water condenser is much more efficient than the typical air cooled condenser, it can keep the refrigerant leaving the condenser much cooler than the outside air temperature, but it uses a lot of water and gets corroded from hard water after a few years, so it is not economically feasible to use them for residential use.
Also the reason they put the solar heater on the roof upside down is because they don't really want to heat it up the refrigerant at all. It looks like the only reason for the solar panel is so they can file for the 30% federal solar tax credit when they sell them.
+kdb4u THANKS! Now you clear up my doubts technically, now I want to share my own real life experiment.
I bought one of these units 12,000 BTU with the solar heater mounted on top of the condenser units like this,
http://dir.indiamart.com/impcat/solar-a ... ioner.html, I installed in a room with few computers servers to keep the place cool 24 hrs a day.
My electric bill should go down as energy saving air conditioner installed, but was the opposite, went up.
I did not give up y bought another 12,000 BTU 24 SEER INVERTER plain AC unit and installed in the same room and put an electric meter just for the air conditioners and used each one of the AC systems for 24 hours each 6 to 6 a.m. on 2 hot days and the AC with the solar heater power consumption was 22 Kw/h the plain 24 SEER INVERTER was 12.5 Kw/h.
I post this to help people not to waste money.
Re: Klima sa solarnom podrškom
Napisan post: 15 Avg 2015, 14:29
napisao Soko
Šalim se. Naravno da ne možeš da znaš.
To objašnjenje koje si postavio može da bude logično da se ne polazi od pogrešne teorije. Kompresor ne troši struju da bi ugrejao freon već da bi mu podigao pritisak a to sa sobom donosi i povećanje temperature samog gasa.
Oni uporno povezuju potrošnju el. energije kompresora sa zagrevanjem freona i pokušavaju da prodaju priču kako se dodatnim zagrevanjem freona zamenjuje rad kompresora i time štedi struja koju on potroši.
Klasična zamena teza - nije cilj da se gasu doda još toplote. Cilj je toplotnu energiju koju on već nosi sa sobom predati okolnom vazduhu što će dovesti do njegovog kondenzovanja.
E sad, pošto je okolni vazduh već topliji nego taj freon, jedini način da se freon učini toplijim a bez dodavanja energije jeste da mu se pritisak podigne.
Potrošnja kompresora i toplota koju on dodaje freonu je nus-efekat zbog ograničenja tehnologije.
Meni je u glavi na prvi pogled bilo jasno zbog čega je ovo treš. Nadao sam se da će mi neko otvoriti oči.
Trudio sam se da svoje misli što konciznije pretočim u tekst. Nadam se da sam uspeo da objasnim.
edit. Mislio sam na tvoje objasnjenje u prethodnoj poruci.
Ovo drugo si postavio dok sam ja pisao moju poruku. Tu je navedeno manje-vise isto sto sam i ja rekao samo malo strucnijom terminologijom obajsnjeno.
Re: Klima sa solarnom podrškom
Napisan post: 01 Sep 2015, 10:37
napisao bolenbgd
poz drustvo
ovo mi liči na iskorištavanje ljudi koji stvarno veruju u energiju prikupljenu solarnim putem , koji znaju da izlaganjem nekog uredjaja suncu dobijate besplatnu toplotnu energiju , i koji imaju novca da uloze u ovu recimo snake oil prevaru
a koji ne znaju baš mnogo o rashladnoj tehnici .
ovo me podseća na jednu od skorasnjih prevara
http://www.amazon.com/Power-Saver-Home- ... B001CJT5Q8
čak su i napravili za upotrebu u automobilima , kad su otvorili uredjaj u njemu je bila samo LE dioda
ovo mi se svidja
http://www.machine-history.com/sites/de ... custom.jpg
al se jos iz skole secam da je potrebno 4x vise elektricne energije u odnosu na kompresione sisteme da bi radili
sad kolko moze solarni kolektor da isporuči toplotne energije da bi ovaj sistem radio efikasno i kad ti treba(tropske noci) to je vec viša matematika