西班牙Abalos+Sentkiewicz AS+事務所

李明陽 LI Mingyang/ 譯

王祥 WANG Xiang/ 校

作為建筑執(zhí)業(yè)者，我們認為設(shè)計師不能只滿足于追求建筑內(nèi)部能量平衡的環(huán)境評估體系，因為其代價是將公共空間當作容納建筑能量耗散的“垃圾箱”。與之相反，在借助參數(shù)化工具和基本熱力學定律實現(xiàn)的建筑設(shè)計中，形式、物質(zhì)、流動達成的平衡關(guān)系將有助于塑造真正的熱力學建筑，它植根于地域性的物質(zhì)文化并融入城市環(huán)境，而非僅僅“寄生”其中。本文將介紹Abalos+Sentkiewicz AS+事務所開發(fā)的有關(guān)建筑熱力學的專業(yè)設(shè)計技術(shù)。

首先用一張闡釋了我們設(shè)計理念的圖來展開說明這個簡短的宣言，如圖1所示，上圖由Foster+Partners事務所高級執(zhí)行合伙人Stefan Behling于2002年創(chuàng)作，下圖則是2013年Abalos+Sentkiewicz AS+事務所對其重新審視后繪制的新版本。Stefan Behling指出，現(xiàn)代建筑在人們的理解中就像“冰箱”一樣，通過隔熱層與外界氣候變化完全隔絕，并借助機械設(shè)備人為地創(chuàng)造出持續(xù)穩(wěn)定的室內(nèi)氣候。人們也理所當然地認為能源平衡問題僅限于建筑內(nèi)部，對排放到街道等公共空間的廢棄物置之不理。而Behling描繪的未來就是我們當下面臨的問題：建筑的形式成為實現(xiàn)能量平衡的關(guān)鍵。針對特定氣候參數(shù)適當?shù)卣{(diào)整設(shè)計方案以達到形式、物質(zhì)、能源流動之間的協(xié)調(diào)，將使得我們可以最大程度地減少建筑物中主動式能量控制系統(tǒng)的使用。這一思想并不新鮮，在以往許多建筑中，適應氣候的設(shè)計策略已經(jīng)成為一種普遍現(xiàn)象。因此，我們在Behling的圖中增加了名為“過去”的三角形，以彌補對本土建筑認知的缺失。建筑師可以從傳統(tǒng)建筑中學到很多，這種學習絕非照搬原樣，而是理解它們的原理并通過現(xiàn)代技術(shù)和材料來重新應用，諸如參數(shù)化軟件之類的工具能幫助我們以一種與靜態(tài)思維相反的動態(tài)方式來應對氣候問題。

研究表明，人們更喜歡具有“熱力學肌理”的空間，即一種具有非對稱熱力學參數(shù)并且在合理范圍內(nèi)變動的空間。這種偏好還與建筑使用者的健康以及身心舒適有關(guān)。因此，這里要強調(diào)的是我們從來不單獨討論熱力學，而是同時關(guān)注建筑學、熱力學和美學這三者的結(jié)合統(tǒng)一。

下文中將通過三個具體的實踐案例來研究三種不同規(guī)模和氣候條件下的建筑類型。雖然這三個原型是針對特定使用情況開發(fā)的，但由于它們的設(shè)計重點是定義外部氣候與人體之間的“接口”，因此也適用于其他項目。我們的做法是定義適合使用者身體舒適度的空間，或提供庇護或使他們置身特定的四季氣候環(huán)境中。

第一個原型是適用于潮濕的亞熱帶氣候的庭院類型，它采用窄開間布局，有利于必要的自然通風，基于對氣流組織的關(guān)注，這種類型界定了用以提升舒適感的外部空間。第二個原型是適用于寒冷干燥的草原氣候的立方體類型，與前者不同的是，它結(jié)構(gòu)緊湊，最大程度地減少了與室外的換熱面積，使室內(nèi)免受大溫差的影響。第三個原型是適用于溫和的地中海氣候的“輕型棚屋”或廠房類型，它能為室外和室內(nèi)空間提供不同的日照條件和良好的通風條件，具有持久的舒適性。

第一個原型的開發(fā)側(cè)重于界定一種裝置，我們可稱之為“人造樹”，這種裝置可以控制空氣和水的流通以調(diào)節(jié)庭院環(huán)境。第二個原型則優(yōu)先考慮貫穿內(nèi)部空間的結(jié)構(gòu)體系升級，使這些空間具有維持在人體舒適度范圍內(nèi)的熱穩(wěn)定性。值得一提的是，這個案例中使用者提出了特殊的濕熱要求（用來滿足藝術(shù)品收藏的嚴格條件），這使我們能夠以極高的精度對設(shè)計進行微調(diào)。這種立方體原型的適用范圍還可以拓展到其他有嚴格環(huán)境要求的情況（如實驗室、檔案館、圖書館等）。最后一個案例中對空間靈活性和多樣性的探索占據(jù)主導，我們試圖尋求一種適應性，使建筑能夠隨著時間推移滿足各種娛樂活動的需求，其中包括了靜態(tài)和動態(tài)的空間，以及私密空間和集體活動空間。

1 珠海當代藝術(shù)博物館（中國珠海，2003-）

珠海當代藝術(shù)博物館是在國際競賽中獲得一等獎的設(shè)計作品（圖2）。該項目位于中國南部的珠江三角洲，毗鄰澳門島，距香港60km。因為世界上最長的港珠澳大橋從這里架起，使得這一項目成為海灣沿岸的一個特殊地塊。我們的項目研究從對當?shù)貧夂虻姆治鲩_始——Koppen-Geiger氣候分類系統(tǒng)顯示該地處于潮濕的亞熱帶氣候區(qū)，具有穩(wěn)定的溫度和極高的濕度。此外，任務書中還包括一個三層的地下停車場，也是設(shè)計方案必須回應的一點。因此，方案設(shè)計的第一步是考慮如何有效地利用停車場的混凝土外墻的熱穩(wěn)定性并使其惠及上部樓層。這一步設(shè)計先是由停車場平面直接生成形體，然后在形體上打開不同的孔洞。在這些孔洞中最重要的是通過內(nèi)部“挖空”所形成的中央庭院組織對流通風，使中庭成為建筑應對高濕氣候的關(guān)鍵。

下一步是根據(jù)建筑與陽光的關(guān)系對屋頂曲線進行處理，以借助輻射來減少屋頂濕度，并通過夜間散熱將熱量傳遞到大氣中，這種方法可以在晚上對建筑物進行熱重置。此外，建筑物的所有外窗均設(shè)計為狹長的豎條狀，既滿足了預期的展覽功能中避免陽光直射的需要，也為室內(nèi)提供了對流通風。這些設(shè)計操作塑造了兩個公共空間：高低起伏的屋頂廣場以及可以進行展覽等戶外活動的有遮蔽的庭院（圖3）。前者利用起伏的屋頂形成了一系列相互連通的露天劇場，作為眺望城市及其周邊地區(qū)的公共看臺；后者則為庭院置入了避雨遮陽的防護措施，成為該項目最獨特的亮點之一。

用于避雨和遮陽的涼棚或“保護傘”的設(shè)計基于兩個基本概念：雨水的收集利用以及整體起伏屋頂形成的視覺連貫性。該系統(tǒng)的靈感來自對龍血樹（Dracaena Cinnabari）的研究，龍血樹的其獨特之處在于，除了能提供寬闊的陰影外，還能利用樹冠從大氣中吸收水分并通過復雜的分支系統(tǒng)分配水分，而不像絕大多數(shù)樹木通過根莖從土壤中吸收水分?；谶@一原理，我們設(shè)置了六棵人造樹（圖4），它們不僅像真正的龍血樹一樣可以收集和分配雨水，還具有調(diào)節(jié)屋頂廣場氣流的作用。

1 熱力學建筑中平衡關(guān)系的設(shè)計理念

2 珠海當代藝術(shù)博物館對岸海灣視角

3 珠海當代藝術(shù)博物館中央庭院

4 珠海當代藝術(shù)博物館珠海熱力人造樹

5 Sorigué 基金會采石場

參與人造樹研發(fā)的工程師Salmaan Craig定義了兩種空氣流通機制：下行模式和上行模式。下行模式是在早上將涼爽的空氣引入庭院，而上行模式則是在下午將高溫空氣排出。具體來說，在夜間不銹鋼人造樹的溫度會下降，第二天早上空氣接觸其表面后被冷卻，而后通過循環(huán)管道網(wǎng)絡引入庭院中，同時晨露蒸發(fā)也有利于降溫。而到了下午某一時刻，隨著鋼材在日照下逐漸升溫，這種下行模式會被上行模式取代，空氣流動的方向隨之反轉(zhuǎn)——人造樹內(nèi)部的空氣被加熱后通過樹木內(nèi)部管道向上流動被排出。

為了確?？諝饬魍C制的正常運行，我們通過精確的幾何規(guī)律確定了這些人造樹的形狀，其底部大開口確保了上行或下行氣流的通暢。從獨立主干開始的一系列分流總共形成了180個分支，這些分支的設(shè)計都遵循同一個原則：每一級分支的管道截面積之和必須保持恒定，以保證氣流平穩(wěn)。這種做法的另一個好處是使管道內(nèi)部具有較大的相對表面積，這意味著結(jié)構(gòu)本身就能發(fā)揮熱交換器的作用來調(diào)節(jié)管道內(nèi)部及其周圍空氣的溫度。建筑整體則面向海灣呈現(xiàn)出富有張力和識別性的形象，作為從香港方向經(jīng)港珠澳大橋驅(qū)車而來的人們進入珠海的門戶，昭示著這座文化設(shè)施背后的宏大藍圖和戰(zhàn)略眼光。

2 Sorigué基金會采石場（西班牙萊里達省巴拉格爾，2016-）

Sorigué基金會采石場項目中，建筑被賦予了當代重要藝術(shù)品收藏的功能（圖5）。項目場地位于一個礫石坑中，在這里我們面對的是寒冷的半干旱草原氣候（BSk）。與前一個案例相比，這個案例中最顯著的氣候特征不是濕度而是溫差，因此精確的熱力漲落圖表成為我們推導項目設(shè)計方法的關(guān)鍵。如圖6所示，該圖收集了白天（紅色）和夜間（藍色）月平均溫度的變化曲線，以及人體熱舒適區(qū)域（黃色）的變化曲線。根據(jù)這些曲線我們可以清楚地認識到，與人體幾乎恒定的熱舒適需求相比，極端的溫度波動已經(jīng)說明了熱穩(wěn)定性作為項目出發(fā)點的重要性。而該項目場地的土層常年保持約14℃（黑色曲線），因此我們決定利用土層的高熱惰性來解決溫差問題。

通過對熱穩(wěn)定的探求，我們收獲了開展設(shè)計的重要線索。一方面，建筑的體形系數(shù)必須是最佳的。因此我們提出了一種緊湊嵌入土壤的立方體作為建筑的基本原型，從而更好地利用土層的熱穩(wěn)定性。另一方面，我們根據(jù)朝向確定了屋頂形式，它的北側(cè)開敞，南向則是封閉的，這樣使得建筑避免了南向的直射陽光，從而滿足保存藝術(shù)品的需要。隨后，我們將這種屋頂形式轉(zhuǎn)移到了建筑立面上，通過將建筑旋轉(zhuǎn)45°并將所有窗戶都向北敞開，實現(xiàn)了最大程度的間接采光。

然而，建筑的熱穩(wěn)定性需要高熱惰性的材料才能實現(xiàn)，這些材料不僅要用于外部覆層，還要用于內(nèi)部空間，特別是結(jié)構(gòu)框架上。因此我們決定采用鋼筋混凝土樓板和墻體，以生成所有內(nèi)部空間并提供均一溫度的連續(xù)結(jié)構(gòu)。通過這樣的設(shè)計，由大量混凝土建成的建筑體現(xiàn)出高度的一體性，其結(jié)構(gòu)和裝飾已然融合成為了一種建筑元素。

我們分析氣候條件的另一個關(guān)鍵工具是一系列精心繪制的焓濕圖（圖7）。其中每組由四張圖表組成，涵蓋了一年中四個季節(jié)的溫濕變化。圖中的每一點代表一年中某一天的溫度和濕度，而“舒適區(qū)”則代表人體舒適的環(huán)境區(qū)間（藍色區(qū)域）。

第一組圖表現(xiàn)了萊里達當?shù)氐臍夂驐l件，我們可以很清晰地觀察到四個季節(jié)中溫度的巨大變化及其與人體舒適溫度的顯著差距。第二組圖則表示了建筑在進行技術(shù)升級之前的室內(nèi)氣候條件，驗證了基于前文所述的形式、物質(zhì)以及流動概念的建筑決策。我們可以觀察到，在不采取其他措施的情況下，春秋兩季有大量的點處于舒適區(qū)范圍內(nèi)，而夏冬兩季則要通過額外的系統(tǒng)介入來調(diào)整與舒適區(qū)差異較大的極端溫度。因此，我們決定對鋼筋混凝土結(jié)構(gòu)進行改進，即在樓板和墻體中預留管道來傳導空氣，使混凝土結(jié)構(gòu)形成一個連續(xù)的管道系統(tǒng)（也被稱為“加拿大管網(wǎng)”），即將經(jīng)過恒溫土層過濾和調(diào)溫的空氣導入室內(nèi)，而不是直接從室外引入空氣。為此，我們設(shè)計了一長條地下管線使外部空氣與土壤可以進行充分的熱交換。最后一組圖表顯示了利用上述系統(tǒng)對建筑進行優(yōu)化后的結(jié)果。從中可以看到，夏季室內(nèi)的高溫問題已經(jīng)解決，而冬季室內(nèi)溫度則略低于舒適標準（主要是由于土層溫度僅為14℃）。在這種情況下，我們認為這樣的結(jié)果是令人滿意的，在敦促游客穿著用以保暖的衣服（如毛衣或輕便外套）的同時，也完全滿足了其他“使用者”（藝術(shù)品）的收藏保護要求。為了進一步達到通用的熱舒適標準，即保證冬天室內(nèi)溫度達到21℃左右，我們也必須采用一些主動式系統(tǒng)。為此我們提出了使用輻射地板采暖系統(tǒng)（圖8），其與使用者的關(guān)系更加緊密，也保證了一年中任何時間的室內(nèi)舒適度。

6 Sorigué 基金會采石場全年熱力波動漲落圖

7 Sorigué 基金會采石場氣候焓濕圖

經(jīng)過土層調(diào)溫的空氣在建筑物內(nèi)的流通遵循兩種機制：對于用作展覽的4m高空間，空氣從天花板處引入。在后者這些較高的空間內(nèi)，大量人群的人體熱輻射和投影儀之類的機器散熱將產(chǎn)生熱量聚集，而相對更加高大的空間尺度則可以使這些積聚的熱量遠離人群。同時，建筑頂層采用鋸齒狀天窗（圖9）促進夏季天花板處積聚空氣的排出，并利用貫穿所有樓層的中庭空間為整個室內(nèi)提供通風，中庭的煙囪效應也可以在夜間對建筑進行熱重置。

綜上所述，我們把這個用作藝術(shù)品收藏和展覽的容器理解為第二種熱力學建筑的原型。設(shè)計中采用的穿孔混凝土框架體系使用了從礫石坑中開采的原材料作為混凝土骨料，這種建造系統(tǒng)具有很高的靈活性，這也使得該原型能夠適用于其他項目。

8 Sorigué 基金會采石場熱力學分析截面

9 Sorigué 基金會采石場Planta 頂層內(nèi)部視圖

10 西班牙Azuqueca de Henares 休閑中心南立面視圖

11 西班牙Azuqueca de Henares 休閑中心室內(nèi)房間景觀

12 西班牙Azuqueca de Henares 休閑中心剖面和模型

3 西班牙Azuqueca de Henares休閑中心（西班牙瓜達拉哈拉省，2007—2011）

西班牙Azuqueca de Henares休閑中心同樣位于西班牙（圖10），但其所處氣候環(huán)境與前兩個案例完全不同，屬于溫和的地中海氣候（Csa）。每年有大約8個月都保持在熱舒適范圍內(nèi)。該項目位于距馬德里100km的一個工業(yè)小鎮(zhèn)，我們在早期通過概念方案的競標獲得了最終設(shè)計權(quán)。休閑中心的功能設(shè)定相對自由，包括計算機室、圖書館、禮堂等。

項目功能的開放定義以及其坐落城鎮(zhèn)所有的工業(yè)建筑特性（后者對項目有重要影響力），促使我們能夠在首層采用一種延展性的單層建筑建造體系。建筑內(nèi)部由無走廊連接的房間組成（圖11），在平面布局上，這些房間構(gòu)成了一個虛實空間相互交錯的矩陣，產(chǎn)生了豐富的效果（內(nèi)外滲透、不同的方位朝向、尺度和光影等），進而塑造了不同的內(nèi)部環(huán)境，也提供了空間的多種用途。方案設(shè)計中包含了一系列相互平行的內(nèi)部庭院，這也是對當?shù)貍鹘y(tǒng)建筑類型La Manch（當?shù)氐膸杜_房屋）中熱力學原理的沿用。功能布置則從朝向出發(fā)：南向主要布置相對安靜的功能，因為在這些空間里使用者主要是就坐的狀態(tài)，可以享受良好的采光；北向則布置一些最為活躍的功能（例如健身房）。

盡管該建筑主要為單層延展的模式，我們?nèi)匀槐ＷC了其內(nèi)部4.20m的充足高度（圖12），這是為了讓積聚的熱空氣始終保持在人體高度之上。設(shè)計采取的其他被動式策略還包括通過露臺進行自然通風以及設(shè)置寬敞的綠化屋頂。由于屋頂可以從周圍的建筑中被清晰地看到，在設(shè)計中也被視為建筑的第五立面進行展示。值得一提的是，這類綠色屋頂在干燥狀態(tài)下具有很好的隔熱能力，因此在地中海氣候區(qū)幾乎沒有降雨的夏季，它能避免建筑受到過多的太陽輻射。建筑的南立面完全由玻璃組成，在冬天被用作大型太陽能暖房，夏天則利用遮陽設(shè)施防止內(nèi)部空間過熱。在建筑南側(cè)，我們還設(shè)置了兩個重要的景觀元素，也是地中海傳統(tǒng)建筑的關(guān)鍵要素：通過絕熱冷卻在夏天發(fā)揮降溫作用的水池和一系列精心種植的落葉樹。它們在夏季可以遮陽，而冬季落葉后能使太陽輻射進入室內(nèi)。

This paper explains the professional design techniques developed at Abalos+Sentkiewicz regarding thermodynamics in architecture.As practitioners,we cannot be satisfied with environmental assessments systems that only consider the interior energy balance of buildings as its goal at the expense of using public space as an energy dissipation dumpster.The balanced relationship between Form/ Matter/ Flow in architectural design -achieved by both parametric tools and basic thermodynamic principlescan contribute to a genuine thermodynamic architecture rooted in local material culture and tuned with the urban environment instead of parasitizing it.

I will extend this short manifesto in a couple of diagrams (fig.1) that define our design philosophy.The upper one was created by the Foster+Partners Senior Executive Partner Stefan Behling in 2002 and the lower one is a review carried out by Abalos+Sentkiewicz in 2013.Stefan Behling states that,during Modernity,the architectural form had a minimal impact on the energy balance.The modern building was understood as a kind of ‘refrigerator’ completely isolated from the climate and its variations through various layers of insulation,while inside that building an artificial,static and continuous climate was recreated by mechanical means.This also supposed that the energy balance concerns ended at the very limits of the building,expelling all toxins to the street or public space.

What Behling proposes as a future horizon is for us the present:architectural form is the key to the energy balance.The coordination between form,matter and flow,properly tuned for the parameters of a specific climate,allows us to minimize active energy control systems in buildings.This is not new.Adaptation to the climate is a well-known phenomenon in many architectures of the past.For this reason,we add to the Behling diagram a third triangle entitled ‘past’,in allusion to the lost knowledge of vernacular architecture.As architects,we have a lot to learn from these traditional architectures.Not to copy them directly,but to understand their principles and be able to apply them through contemporary techniques and materials,such as,for example,parametric software.This kind of tools helps us to operate with the climate in a dynamic way opposite to the static understanding of Modernity.When usually show a series of references of historical architectures associated with some images of thermal machines,what we mean is that our architecture is located right in the middle of them,working at the same time with both resources,History of Architecture and technology.

Studies show that people prefer ‘thermally textured’spaces where thermal parameters,within reasonable limits,are asymmetric and changeable.This preference is also related to health and physical and psychological well-being of architecture users.I would like to highlight that we never talk about thermodynamics,but about architecture,thermodynamics and beauty at the same time.

We are going to study,by means of particular examples of our practice,three building types with different scales and climatic conditions.These three prototypes have been developed for certain uses,but could be adapted to other programs,since their design is focused on defining,above all,an 'interface' between the external climate and the human body.Our practice defines spaces adapted to user’s bodies,protecting them or exposing them to specific conditions of climate and its variations throughout the year.In the first place,the courtyard type has been applied to a humid subtropical climate,adopting narrow bays that facilitate the necessary natural ventilation.Focused on managing air flows,this type defines an exterior space conditioned for human comfort.In the second place,the cube type has been applied to a cold,dry steppe climate.Unlike the previous one,it is compact and protects its interior from large temperature differences reducing to maximum the exchange surface with the exterior.Finally,the extensive or ‘lightweight shed’ (factory) type,used in a warm Mediterranean climate with a long period of human comfort,manages climate resources by defining exterior and interior rooms with different exposure to the sun and generous volumes of air.

The development of the first prototype focuses on the definition of devices or "artificial trees" that manage air and water flows to condition the courtyard.The second case prioritizes the development of an internal skeleton that crosses all spaces,providing them with thermal stability within the limits of human comfort.In this case,it is relevant to mention that the hygrothermal needs of a different user,an art collection with strict conservation conditions,led us to fine-tuning the design with great precision.This prototype of cube-type could also contain other demanding programs,such as laboratories,archives,libraries,etc.In the third and last case study,a Leisure Center (Factory type),the search for flexibility and variety of spaces has prevailed,seeking for adaptation over time to different recreational activities,static and dynamic,collective or individual.

Zhuhai Contemporary Art Museum.Zhuhai,China.2013-

The Zhuhai Museum of Contemporary Art (fig.2) is the result of a first prize awarded entry in an international competition.Located in the south of China,in the Pearl River delta,the project settled in a privileged plot on the bay shore,next to the island of Macao and 60 km away from Hong Kong.From this same point,the longest bridge in the world starts,connecting Zhuhai,Hong Kong and Macao.When we study a new project,we always start from the analysis of the local climate.The Koppen-Geiger climate classification indicates that we are in a humid subtropical climate (Cwa) with stable temperatures and extreme humidity.The tender statement included the project of a three-storey underground carpark that had to be respected by the proposal.The first operation of the project uses this concrete shell of the car park as an opportunity to use its thermal stability and take it to the upper levels above.This operation starts with the almost direct extrusion of the carpark footprint.Then,this volume is drilled by diverse openings.The most important of them is the central courtyard of the building that is ‘hollowed out’ inside.The courtyard is the key piece to combat high humidity by allowing cross ventilation around the central void.

The next step articulates the roof based on curves that interact with the sun,using radiation to reduce the humidity of the roof,as well as to transfer heat to the atmosphere by night irradiation,a method that allows us to thermally reset the building at night.All the exterior windows of the building are shaped as narrow vertical strips preventing the incidence of direct solar radiation,undesirable for the intended exhibition use,at the same time as allowing cross ventilation.With these design operations,two public spaces are generated:a topographic plaza on the rooftop and a covered courtyard (fig.3) capable of hosting exhibitions and outdoor uses.The first one uses the waves from the roof to shape a succession of concatenated amphitheaters.The result is a public observatory of the city of Zhuhai and its surroundings.On the other hand,the exterior space of the patio follows a protection strategy against rain and solar radiation that will be one of the most unique features of the project.

The design of pergolas or ‘umbrellas’ for shading and sun protection started from two basic ideas:the capture of rainwater for the use of the building,and the visual continuation of the topography of the roof by virtually completing the spatial unity of the whole.The form of this system is inspired by the study of the dracaena cinnabari or "dragon's blood tree" whose peculiarity lies in the fact that -in addition to providing a generous shade-it does not collect water from the underground with its roots,as most trees do,but it absorbs moisture from atmospheric air through its top and distributes it through the sophisticated geometry of its branches.In this way,six artificial trees inspired by the dragon tree are proposed (fig.4),which not only collect and distribute rainwater,similar to its organic predecessor,but also are used to manage the air flows in the patio.

The engineer Salmaan Craig collaborated in the development of these trees defining two flow functioning regimes:flow down (descending) and flow up (ascending).Down-draft brings the cool air to the courtyard in the morning and up-draft take up the hot air in the afternoon.The temperature of the stainless-steel mass of the tree drops during the night and when the morning comes it cools the air in contact with its surface making it descend into the courtyard through the interior of its network of circular tubes.Also,the humidity of the morning dew begins to evaporate with the first sun rays,contributing to the drop-in air temperature around it.This flow down strategy is substituted,at a point of the afternoon,by a flow up operation as the mass of the tree is heated by the sun.At this moment,the operation of the air flow is reversed:the air inside the tree is heated through its mass and starts to be expelled up through the trees.

To allow its correct operation,the shape of the trees has been carefully established by very precise geometric laws.At their base,they have a large opening that allows upward and downward flow.Starting from a single trunk,a series of bifurcations are made up to a higher level of 180 branches.The design principle of this structure dictates that the sum of the areas of the tube sections must be constant in order to maintain a homogeneous air flow.One of the effects of this design is a very high surface ratio versus the volume of air contained.This means that the tree itself functions as a heat exchanger that tempers the temperature of the air inside and around it.

The whole shows a powerful and recognizable image from the bay,necessary to give visibility to a cultural program of great ambition and strategic interest,being the gateway to Zhuhai for drivers who cross the bridge from Hong Kong.

PLANTA Project for Sorigue foundation.Balaguer,Lleida,Spain.2016-

Located in a gravel pit (fig.5) in a completely different climate and location,a building is commissioned to contain an important collection of contemporary art.In this case,we dealt with a cold,semi-arid steppe climate(BSk).Compared to the previous case study,in this case,the most significant feature of this climate is not humidity but rather high temperature contrasts.The elaboration of an accurate diagram of thermal oscillations has been key to define the design approach of our project.This diagram collects the variation curves of the monthly average temperature during the day (red) and night (blue) as well as the human thermal comfort area (yellow).At first glance,we can recognize that the extreme oscillation of temperatures,compared to the almost constant demands of human users,already indicates the importance of the search for thermal stability as a crucial project resource.For this reason,we have resorted to the high thermal inertia of the terrain (black curve),which maintains a temperature of around 14 degrees throughout the year (fig.6).

The search for stability already gives us important clues about design.On one hand,the form factor of the building,the relation between contained volume and exchange surface,must be optimal.Therefore,a compact form is proposed -a cube-which,to make use of the thermal stability of the soil,is embedded into the ground.On the other hand,the roof is shaped according to the solar orientations,opening us to the north and closing us to the south.In this way,we achieve adequate protection against direct solar radiation (necessary for the conservation of works of art).Later,we transferred this deformation of the roof to the facades,rotating the building 45 degrees in order to achieve the maximum indirect natural lighting from the north orientation,to which all the windows of the building open.

Seeking stability at the building demands a material of great inertia.Not only for the exterior cladding but especially for the interior structural skeleton.We decided to work with reinforced concrete slabs and walls,generating a continuous structure that runs through all the interior spaces and provides them with a uniform temperature.The result is a monolithic building where extensive use is made of concrete and where structure and finish are one and the same architectural element.

Another key tool for the analysis of climatic conditions is the elaboration of diverse series of psychrometric charts (fig.7).Each series is made up of four diagrams,one per season of the year,in which the points represent the temperature and humidity of every day of the year and the so-called ‘comfort zone’ represents the environmental limits of human well-being (blue area).

The first series represents the local climate of Lleida.The enormous variation between temperatures and its significant distance to comfort parameters can be easily observed.The second series represents the interior conditions of the building before its technical development,testing the architectural decisions of the aforementioned concepts of form,matter and flow.A considerable grouping of the points representing the daily temperatures is observed,guaranteeing comfort in spring and autumn,without using other means.Finally,another series of systems come on the scene to raise and lower the extreme temperatures of winter and summer that are still far from comfort standards.For this reason,it was decided to temper the reinforced concrete structural shell with air conducted through cloistered pipes inside slabs and walls.The concrete skeleton thus constitutes a continuous system of ducts through which air circulates not introduced directly from the outside,but filtered and tempered by the stabilizing action of the terrain.To do this we designed a long underground route so that the outside air exchanges heat with the soil.Then,a last series of diagrams shows the result of the building optimized by the incorporation of this so-called “Canadian tubes” system.In summer,the problems of high indoor temperatures have disappeared,while in winter the temperatures are slightly below comfort standards (remember that the temperature of the terrain is around 14°C).In this case,we could consider these results to be satisfactory,appealing that the visitor would have to wear some kind of warm clothing(as a sweater or light coat).Likewise,the art collection conservation environmental requirements,the ‘other’ user of our building,are already fully satisfied.To reach these mentioned conditions to the common standard comfort levels,that is,an interior temperature of around 21°C in winter,we have to implement some active systems.We proposed a radiant floor heating system,acting on a plane closer to the user for allowing us to guarantee interior comfort twelve months a year (fig.8).

The diffusion of the filtered and tempered air inside the building follows two schemes.For spaces 4 meters high,generally intended for exhibition uses,the air is blown down from the ceiling,while in spaces with higher heights it is blown up from below.These taller spaces are meant to have thermal gains by radiation from human bodies (greater audience attendance) and/or by machines such as video projectors,so that the greater height allows the accumulation of hot air away from user’s comfort zone.Likewise,on the upper floor,the sawtooth skylights(fig.9) enhance the evacuation of the air accumulated at the ceiling in the summer months,allowing ventilation of the entire interior by means of a vertical communication core that crosses all the floors of the building and is capable of function as a night time buoyancy chimney that thermally resets the building.

We understand the building as a thermodynamic prototype,used here as a container for an art collection and its exhibition.However,this container could be adapted to many other programs thanks to the great flexibility of its construction system based on a perforated concrete skeleton that uses local aggregates extracted from the same gravel pit where it is inserted as its main raw material.

Leisure Center.Azuqueca de Henares,Guadalajara,Spain.2007-2011

The third case study,also located in Spain,presents,however,a totally different climate from the previous two:what we can describe as warm Mediterranean (Csa).Much more benevolent than the other climates previously mentioned,the Mediterranean climate maintains comfort conditions around eight months a year.

The project (fig.10),located in Azuqueca de Henares,a small industrial town one hundred kilometers from Madrid,was the result of a contest won by Abalos +Sentkiewicz with an ambiguous leisure center program,which included computer rooms,library,auditorium,etc.The open definition of the program together with the industrial architectural -which have a strong presence in the location-favored the adoption of an extensive single floor constructive system at ground level.The interior is configured as a collection of rooms connected without corridors (fig.11).This sum of rooms shapes a matrix of full and empty spaces with very rich results:interior and exterior spaces,different orientations,sizes and lights,which allow a wide range of uses and environments to be established inside.This solution also remembers thethermodynamic functioning of a traditional type (La Mancha vernacular patio house),also configured by a succession of parallel bays with interior courtyards.The proposed program configuration relay on the tension between the south and north orientations to arrange the uses:the south-oriented uses are static programs,exposed to the sun where the user is mainly seated.On the other hand,the most active programs,such as the gym,are oriented to the north.

Despite the fact that the building is developed mainly on a single floor,its interior height is significant (4.20 meters high) (fig.12),in order to keep the accumulated hot air above the height of the human body.Other passive strategies implemented are natural cross-ventilation through patios,and an extensive green roof,conceived as a fifth facade as it is clearly visible from the surrounding buildings.It should be remembered here that these types of green roofs have a great insulation capacity as long as they are dry,so in this case,it will act in summer protecting from excessive solar radiation in a period in which there is hardly any rainfall in the Mediterranean climate.The south fa?ade of the building is completely glazed,so that it serves as a large solar collector in winter while in summer it is protected with awnings to prevent interior spaces from overheating.In front of this south facade,we place two important landscaping elements that are key in the Mediterranean tradition:a water pond,that allows the temperature to drop in the summer by adiabatic cooling,and a series of precisely planted deciduous trees,which provide shading in summer while allowing solar radiation in winter.

We wouldn’t like to conclude this article without mentioning the team of world-class specialists who have collaborated with us in these and other innovative projects that constitute what we have named as ‘thermodynamic architecture’.Salmaan Craig (Zhuhai Museum of Contemporary Art),Aleksandar Ivancic and Oriol Gavalda from Aiguasol (Plant Project for the Sorigué Foundation),and Florencio Manteca and Philip Van den Enden from Cener (Leisure Center in Azuqueca de Henares).They have allowed us to fine-tune each of the taken decisions,as well as to technically develop,with accuracy and precision,every technical solution we proposed as architects.