Stand at the bottom of the wall and look straight up.<\/p>\n
What runs from the pavement to the parapet is not glass and not stone. It is a row of fins<\/strong>, narrow and vertical, repeating all the way around the curve.<\/p>\n One side of each fin is timber, gone silver<\/strong> in the weather.<\/p>\n The other side is a solar panel, standing on its edge<\/strong>, facing sideways at the sky rather than up at it.<\/p>\n Nobody puts panels there if the roof will do.<\/p>\n A roof has a fixed size. Whatever the footprint of a building is, that is what the roof gives you, and stacking another floor on top does not add a single square foot<\/strong> to it.<\/p>\n The walls do not work that way.<\/p>\n Every floor you add wraps another band of surface around the perimeter, so the taller the building the further ahead the walls pull. At six stories on a footprint this size the facade area passes the roof outright.<\/p>\n Vertical panels are the worse deal, and everybody involved knew it. Sunlight arrives at a glancing angle<\/strong> on a wall instead of falling square onto it, so the same panel turned upright gives back less over a year.<\/p>\n But there is a great deal more wall than roof.<\/p>\n That is the whole trade. Turn the fins to follow the sun path across the day, accept the loss per panel, and take the win on sheer area<\/strong>.<\/p>\n The city hall is a long curve rather than a block, which puts more perimeter against the same floor area and gives every desk a window. The fins then do three jobs at once<\/strong>.<\/p>\n They carry the panels, they shade the glass behind them from summer sun, and their timber flanks are untreated local larch<\/strong> left to grey on its own rather than sealed and repainted every few years.<\/p>\n Between them sit floor to ceiling windows in triple glazing<\/strong>.<\/p>\n Underneath, the heating and cooling come out of the ground. Water is drawn from wells, run through two heat pumps<\/strong>, and injected back, while the concrete floors themselves are used as the radiator and the ventilation runs through heat recovery.<\/p>\n The roof carries 440 kilowatts<\/strong> of solar and the facade carries another 220, so a third of the generation comes off surfaces a conventional building would have finished in render and forgotten.<\/p>\n The building runs to about 260,000 square feet<\/strong> and holds 840 desks, with a citizens’ service center adding roughly a hundred more.<\/p>\n Demand is where the real work sits. Measured against a comparable modern office block, this one is designed to run on around 40 percent<\/strong> of the primary energy, which is what makes 660 kilowatts of panels enough to close the balance at all.<\/p>\n It opened in late autumn eight years ago and has been monitored ever since by a solar research institute in the same city. Their verdict on the first full operating year was careful rather than triumphant, describing the plus energy target as almost achieved<\/strong>.<\/p>\n That word is doing real work and deserves to stay. A building designed to end the year in surplus and finishing just short is a normal outcome, because the gap between a model and a working office is people leaving screens on<\/strong>.<\/p>\n The vertical panels also do what physics said. They earn less per square foot than the roof array and always will, much as a capped landfill<\/a> is worth roofing for its area and not its quality.<\/p>\n Climate helps too. This is a mild corner of Europe with one of the better solar resources in the country, and the same design set down further north would not balance<\/strong> without changes.<\/p>\n None of that is a knock on the result. It is the difference between a building that performs and a building that claims to<\/strong>, and the second kind is far more common.<\/p>\n The idea worth taking away is not the megawatts. It is that the outside of a building stopped being only weather protection<\/strong>.<\/p>\n A facade has always been a cost. It keeps rain out, holds heat in and looks like something, and every square foot is money that never earns anything<\/strong> back.<\/p>\n Put generation into it and the arithmetic inverts, the way an ordinary road surface<\/a> changes character once it is asked to do a second job.<\/p>\n That matters far more in a city than in a field. Land is the thing cities do not have, and a dense downtown has enormous vertical surface<\/strong> standing idle, which is what the monitoring work<\/a> on this building was set up to test.<\/p>\n What it proved is narrow and useful. A wall can pay for part of itself, the panels on it will underperform the ones on the roof, and there is far more wall<\/a> than there is roof<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" Stand at the bottom of the wall and look straight up. What runs from the pavement to the parapet is not glass and not stone. It is a row of fins, narrow and vertical, repeating all the way around the curve. One side of each fin is timber, gone silver in the weather. The other side is a … Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":33176,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"Germany","rank_math_title":"","rank_math_description":"","footnotes":""},"categories":[8],"tags":[],"class_list":["post-33173","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-energy"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/33173","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=33173"}],"version-history":[{"count":0,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/33173\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/33176"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=33173"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=33173"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=33173"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Why the roof was never going to be enough<\/h2>\n
What the building is made of<\/h2>\n
Where the numbers come from<\/h2>\n
What almost means<\/h2>\n
What a wall is worth<\/h2>\n