Stack effect

Stack effect
physical phenomenon (en)
Bayanai
Yana haddasa	infiltration (en)
Defining formula (en)	${\displaystyle \Delta P=\;C\,a\;h\;{\bigg (}{\frac {1}{T_{o}}}-{\frac {1}{T_{i}}}{\bigg )}}$

Tasirin bututu (stack effect) ko tasirin hayaƙi (chimney effect) shi ne motsin iska shiga da fita daga gine-gine ta ramukan da ba a rufe su sosai ba, bututun hayaƙi, manyan bututun fitar da iskar hayaƙi, ko wasu ramuka ko hanyoyin da aka tsara musamman domin shigarwa da fitar da iska. Wannan motsin iska yana faruwa ne sakamakon ɗagawar iska (buoyancy).

Ɗagawar iska tana faruwa ne saboda bambancin yawan iskar da ke cikin gini da ta waje wanda ke samuwa sakamakon bambancin yanayin zafi da danshi. Hakan na iya haifar da ƙarfin ɗagawar iska mai kyau ko mara kyau. Yayin da bambancin zafin jiki da kuma tsayin ginin suke ƙaruwa, haka ƙarfin ɗagawar iska yake ƙaruwa, wanda hakan ke ƙara tasirin stack.

A wasu yanayi na sauyin yanayi, ana iya amfani da tasirin stack wajen samar da iska ta dabi'a a cikin gine-gine. Sai dai a wasu yanayi, yana iya zama sanadin shigar iska ba tare da so ba ko kuma ƙara haɗarin gobara.

Saboda gine-gine ba sa kasancewa a rufe gaba ɗaya ba, domin aƙalla koyaushe akwai ƙofar shiga a matakin ƙasa, tasirin stack (stack effect) yana haifar da shigar iska cikin gini.

A lokacin sanyi, iskar cikin gini mai ɗumi tana tashi zuwa sama ta cikin ginin, sannan ta fita daga saman ginin ta tagogin da aka buɗe, ramukan samun iska, ko kuma ƙananan ramukan da ba a yi niyyar samarwa ba a cikin rufi, kamar waɗanda ke kusa da fan ɗin rufi da fitilun da aka saka cikin rufi. Tashin iskar ɗumi yana rage matsin iska a ƙasan ginin, wanda ke jawo iska mai sanyi ta shigo ta ƙofofin da aka buɗe, tagogi, ko wasu ramuka da wuraren da iska ke iya ratsawa.

A lokacin zafi, tasirin stack yana faruwa ta akasin wannan hanya, amma yawanci yana da rauni saboda bambancin yanayin zafi tsakanin cikin gini da wajen gini ya fi ƙanƙanta.

A cikin wani zamani mai hawa da yawa, wato gini mai tsayi wanda ke da ambulan ɗin gini (building envelope) mai kyau wajen hana shigar iska, tasirin stack na iya haifar da babban bambanci a matsin iska. Saboda haka, dole ne a yi la’akari da wannan yayin tsara ginin, kuma a wasu lokuta ana buƙatar magance matsalar ta hanyar tsarin samun iska na inji.

Matakalan hawa, ramukan bututu da sauran hanyoyin tsaye, lif da makamantansu suna taimakawa wajen ƙara tasirin stack. A gefe guda, bangon raba ɗakuna, benaye, da tsarin raba gine-gine domin hana yaɗuwar gobara na iya rage wannan tasiri.

Musamman idan gobara ta tashi, yana da matuƙar muhimmanci a sarrafa tasirin stack domin hana yaɗuwar hayaki da wuta, da kuma tabbatar da cewa yanayin cikin ginin ya kasance mai aminci ga mazauna da ma'aikatan kashe gobara.^[1] Ko da yake hanyoyin samar da iska ta dabi'a na iya yin tasiri, kamar sanya wuraren fitar da iska kusa da ƙasa, ana fi son amfani da tsarin samun iska na inji a gine-gine masu tsayi ko kuma gine-ginen da ke da ƙarancin sarari.

Fitar da hayaki na daga cikin muhimman abubuwan da ya kamata a yi la’akari da su a sabbin gine-gine, kuma dole ne a tantance shi tun a lokacin matakan tsara da ƙera ginin.^[2]

Tasirin stack (tasirin hawan iska saboda bambancin zafi da sanyi) na iya kuma ƙara tsananta yaɗuwar gobara, musamman a cikin dogayen gine-gine inda kura-kuran ƙira ke ba da damar samuwar iska mai ƙarfi ko motsin iska da ba a so. Misalan irin waɗannan sun haɗa da gobarar ramin Kaprun, gobarar tashar jirgin ƙasa ta ƙarƙashin ƙasa ta King’s Cross, da kuma gobarar Grenfell Tower, wadda ta yi sanadin mutuwar mutane 72.^[3] Wannan na ƙarshe daga cikin waɗannan ya kasance a wani ɓangare ya kara tsanantawa ta hanyar tasirin tarin, lokacin da rami tsakanin murfin aluminum na waje da rufin ciki ba tare da saninsa ba ya samar da bututun wuta kuma ya jawo wuta sama. Har ila yau, an yi amfani da shi a matsayin babban abin da ke ba da gudummawa a cikin gobarar Kotun Wang Fuk ta 2025 a Hong Kong.^[4]

Sakamakon tarin a cikin tarin iskar gas na masana'antu yayi kama da na gine-gine, sai dai cewa ya haɗa da iskar gas mai zafi da ke da bambancin zafin jiki tare da iska ta waje. Bugu da ƙari, tarin iskar gas na masana'antu yawanci yana ba da ƙarancin cikas ga iskar gas tare da tsawonsa kuma, a zahiri, an inganta shi don haɓaka tasirin tarin don rage bukatun makamashi na fan.

Babban bambance-bambance na zafin jiki tsakanin iska ta waje da iskar gas na iya haifar da tasiri mai karfi a cikin bututun wuta don gine-gine ta amfani da wuta don dumama.

Kafin ci gaban manyan magoya bayan, ana iska da ma'adanai ta amfani da tasirin tarin. Wani rami da aka saukar ya ba da izinin iska a cikin ma'adinai. A ƙasan ragowar da aka ɗaga an ci gaba da ƙone wuta. Shafin (yawanci daruruwan yadudduka masu zurfi) ya nuna kamar murhu kuma iska ta tashi ta hanyarsa tana jawo iska mai kyau a cikin tarin da aka rushe da kewaye da ma'adinai.

Akwai bambancin matsin lamba tsakanin iska ta waje da iska a cikin ginin wanda ya haifar da bambancin zafin jiki tsakanin iska ta ciki da iska ta ciki. Wannan bambancin matsin lamba (ΔP) shine ƙarfin motsawa don tasirin tarin kuma ana iya lissafa shi tare da daidaitattun da aka gabatar a ƙasa.^[8][9] Da daidaitattun suna aiki ne kawai ga gine-gine inda iska take a ciki da waje da gine-gine. Ga gine-ginen da ke da bene ɗaya ko biyu, h shine tsawo na ginin. Ga bene mai yawa, gine-gine masu tsawo, h shine nesa daga budewa a matakin matsin lamba (NPL) na ginin zuwa ko dai mafi girman budewa ko mafi ƙasƙanci. Reference ^[8] ya bayyana yadda NPL ke shafar tasirin tarin a cikin gine-gine masu tsawo.

Ga tarin iskar gas da bututun wuta, inda iska take a waje kuma iskar gas din konewa tana cikin ciki, daidaitattun za su samar da kusanci kawai kuma h shine tsawo na tarin iskar iska ko bututun wuta.

${\displaystyle \Delta P=Cah{\bigg (}{\frac {1}{T_{o}}}-{\frac {1}{T_{i}}}{\bigg )}}$

Rukunin SI:

Ƙungiyoyin al'ada na Amurka:

Za'a iya lissafin ƙididdigar ƙididdigarsa (ƙididdigar da aka tsara a cikin Turanci na Burtaniya) wanda tasirin tarin ya haifar tare da daidaitattun da aka gabatar a ƙasa.^[10] Daidaitawar ta shafi gine-gine inda iska take a ciki da waje da gine-gine. GA gine-gine tare da bene ɗaya ko biyu, h shine tsawo na ginin kuma A shine yankin kwarara na ramuka. GA bene mai yawa, gine-gine masu tsawo, A sh yankin kwarara na budewa kuma h shine nesa daga budewa a matakin matsin lamba (NPL) na ginin zuwa ko dai mafi girman budewa ko mafi ƙasƙanci. Reference ya bayyana yadda NPL ke shafar tasirin tarin a cikin gine-gine masu tsawo.^[8]

Ga tarin iskar gas ko bututun wuta, inda iska ke waje kuma iskar gas mai konewa tana ciki, daidaitattun zai samar da kusanci kawai. hA ila yau, A shine yankin kwarara na giciye kuma h shine tsawo na tarin iskar gas ko bututun wuta.

${\displaystyle Q=CA{\sqrt {2gh{\frac {T_{i}-T_{o}}{T_{i}}}}}}$

Rukunin SI:

Ƙungiyoyin al'ada na Amurka:

Wannan daidaitattun yana ɗauka C juriya ga kwararar dabara yayi kama da juriya na kwararar ta hanyar rami wanda ke da alamar fitarwa C.

• Cross ventilation
• Draft (boiler)
• Ekibastuz GRES-2 Power Station
• HVAC (heating, ventilation and air conditioning)
• Inco Superstack
• Solar chimney
• Solar updraft tower
• Ventilation shaft
• Windcatcher

1. ↑ "Fire Research Division". NIST. Dec 11, 2008 – via www.nist.gov.
2. ↑ "Smoke Simulation: Heat and Smoke Extraction for Building Design". SimScale. 2019-04-23. Retrieved 2019-07-04.
3. ↑ "Grenfell Tower final death toll: police say 71 lives lost as result of fire". The Guardian. 16 November 2017. Retrieved 16 November 2017.
4. ↑ Sinha, Sujita. "How faulty fire barriers helped flames race up the Hong Kong tower". Interesting Engineering (in Turanci). Retrieved 28 November 2025.
5. ↑ Holder, Hugh (2020-11-20). "Stack Effect Strategies for Tropical Homes". Architropics (in Turanci). Retrieved 2024-08-07.
6. 1 2 Rezadoost Dezfuli, Raziyeh; Bazazzadeh, Hassan; Taban, Mohsen; Mahdavinejad, Mohammadjavad (2023-12-01). "Optimizing stack ventilation in low and medium-rise residential buildings in hot and semi-humid climate". Case Studies in Thermal Engineering. 52. doi:10.1016/j.csite.2023.103555. ISSN 2214-157X.
7. ↑ Hosseini, S. H.; Shokry, E.; Ahmadian Hosseini, A. J.; Ahmadi, G.; Calautit, J. K. (2016-12-01). "Evaluation of airflow and thermal comfort in buildings ventilated with wind catchers: Simulation of conditions in Yazd City, Iran". Energy for Sustainable Development. 35: 7–24. Bibcode:2016ESusD..35....7H. doi:10.1016/j.esd.2016.09.005. ISSN 0973-0826.
8. 1 2 3 Magyar, Zoltán. "Natural Ventilation Lecture 2" (PDF). Archived from the original (PDF) on 12 February 2020. Retrieved 12 February 2020.
9. ↑ "Educational Package Ventilation - Lecture 3 : Mechanical (forced) ventilation" (PDF). www.energiazero.org. IDES_EDU / Intelligent Energy Europe. 28 October 2011. Archived from the original (PDF) on 20 January 2020. Retrieved 4 October 2019.
10. ↑ Andy Walker (2 August 2016). "Natural Ventilation". WBDG - Whole Building Design Guide. National Institute of Building Sciences. Retrieved 1 April 2020.