The Menred Group’s Green Building Indus­trial Park in Wenzhou City covers an area of over 60,000 square meters. The photo­voltaic panels installed in the devel­op­ment generate more than one million kilo­watt hours of elec­trical power per year. As a result, the system saves almost 1,000 metric tons of CO₂ per year compared to coal power gener­a­tion. Low-energy tech­nology for carbon neutrality. In addi­tion to facto­ries and office build­ings, the Holiday Campus is located in the climate-neutral indus­trial park. The building has many uses, including as a hotel for corpo­rate guests and, in line with Menred’s mission – inno­va­tion for carbon neutrality in build­ings – it is a ultra-low energy building.

Build­ings like this are an impor­tant step towards carbon neutrality: They consume almost no energy and emit very small amounts of CO₂ during their life­time. Partic­u­larly econom­ical tech­nolo­gies such as heat pumps and air handling units with heat recovery are there­fore used for heating, cooling and venti­lation. The little energy required is ideally gener­ated by the building itself, for example using solar heating for hot water and photo­voltaics on the roof. As a result, the building’s total energy require­ments and CO₂ emis­sions are virtu­ally zero.

(Photo | Una Zhu)

Sustain­able strategy since 1995

Since it was founded in 1995, the Menred Group has been manu­fac­turing envi­ron­men­tally friendly prod­ucts for build­ings like these in the areas of air condi­tioning, heating, fresh air, water treat­ment and smart homes. In fact they have already been working with ebm-papst on resi­den­tial venti­lation for ten years: “Systems like venti­lation systems run 24 hours, 365 days a year. Effi­ciency and reli­a­bility are our customers’ most impor­tant concerns, so the fans have to meet the highest stan­dards – hence our long-standing collab­o­ra­tion with ebm-papst,” explains Chen Wei, General Manager of Zhejiang MENRED Envi­ron­mental Tech­nology Co., Ltd. The company’s sustain­able tech­nolo­gies are turning new build­ings around the world into ultra-low energy build­ings, while existing build­ings can also be retro­fitted for energy effi­ciency.

“Venti­lation systems run 24 hours, 365 days a year. Effi­ciency and reli­a­bility are our customers’ most impor­tant concerns, so the fans have to meet the highest stan­dards.”

Chen Wei, General Manager at Menred

Plan­ning for the Holiday Campus began in 2012, and it was completed in 2017. The building houses many different areas under one roof: rooms for guests, lounges and meeting rooms, a play­room and adven­ture room for chil­dren. Each room has different climate and venti­lation require­ments, but must offer comfort and a pleasant envi­ron­ment for users at all times. How can this be recon­ciled with the ultra-low-energy stan­dard? Where can the most energy and CO₂ be saved?

From previous building expe­ri­ence, the plan­ning team knew that venti­lation and air-condi­tioning systems in their region account for the largest share of energy require­ments, at around 70 percent – so the poten­tial for savings was partic­u­larly high. On the other hand, the site was very dynamic: a changing number of hotel guests, at some­times a fully occu­pied play­room with chil­dren romping around or an impor­tant busi­ness meeting with customers. The result was a wide variety of rapidly changing require­ments for heating, venti­lation, dehu­mid­i­fi­ca­tion and air purifi­ca­tion.

There is a control panel in each room of the Holiday Campus, here for setting the room temper­a­ture. (Photo | Una Zhu)

With the help of the smart home system, Menred always keeps track of current consump­tion values. (Photo | Una Zhu)

Here, under­floor convec­tors provide comfort­able temper­a­tures. (Photo | Una Zhu)

Mix of fans for effi­ciency

The plan­ning team made a deci­sion: A total of 13 fans, including several different models, were to be used in the Holiday Campus – hand-picked to best suit each floor or room. Three aspects were crucial to Menred in the selec­tion process: energy savings, comfort for resi­dents (meaning a minimum noise level), and the possi­bility of adjusting the fan speed as needed. The fans had to be control­lable because the Holiday Campus has a smart building manage­ment system, a MiBEE smart home system that coor­di­nates systems such as air condi­tioning, venti­lation and under­floor heating in real time. Sensors measure the CO₂ and mois­ture content in the air, among other things. Based on these measure­ments, the systems ensure optimum air quality to guar­antee the health and well-being of the people in the rooms.

The music room on the second floor, for example, is usually very busy, which is why Menred installed a ceiling venti­lation system there with connected temper­a­ture control. Depending on the number of people in the room, the system cools or heats it accord­ingly. The system contains four centrifugal blowers that draw in and distribute air effi­ciently and with minimal noise. An inte­grated heat pump for heating and venti­lation.

How the Holiday Campus heats and venti­lates

The photo­voltaic system on the roof of the building supplies the Holiday Campus with elec­tricity. When there is a surplus, the elec­tricity is fed into the grid.

Via tunnels, fresh air is fed to the venti­lation systems in the building.

The heat pump in the base­ment of the Holiday Campus is connected to district heating.

In the play­room, floor heating ensures the right temper­a­ture.

The region can get very hot in the summer. Cooling panels in the ceiling keep the Holiday Campus hotel rooms pleas­antly cool.

The under­floor convec­tors blend unob­tru­sively into the meeting rooms and ensure pleasant temper­a­tures.

The ceiling venti­lation systems venti­late the rooms and are supplied with fresh air from outside via ducts.

This fresh air unit provides the music room with pleas­antly tempered air.

The hot water tank supplies the under­floor heating with the neces­sary water.

With inno­va­tion to the CO₂-neutral building

On the third floor of the Holiday Campus, Menred installed an inno­v­a­tive solu­tion: an inte­grated heat pump envi­ron­ment control unit, or “IEU,” that combines air condi­tioning, purifi­ca­tion and dehu­mid­i­fi­ca­tion in a single device. Inside, there are two centrifugal blowers and one forward-curved motor-impeller per unit. “The combi­na­tion of these fans results in energy recovery at 70 percent in cooling mode and 78 percent in heating mode. This exceeds the tech­nical stan­dards for ultra-low energy build­ings and is a new, envi­ron­men­tally friendly solu­tion for resi­den­tial build­ings,” explains Chen Wei. The annual energy consump­tion of the fresh air unit in the Holiday Campus is only 15 kWh/m², which is below the stan­dard value for ultra-low energy building.

Of course, the energy consump­tion of the entire Campus is also measured and moni­tored at all times. The Menred team can not only see the current energy consump­tion and oper­ating status on the control panel, but also draw conclu­sions for the future. Where can even more energy or CO₂ be saved? Not only in the Holiday Campus, but in all build­ings that are equipped with their effi­cient tech­nology.