In the heart of Malaysia's urban landscape, a quiet energy revolution is using the sun's heat to meet the soaring demands of high-rise living.
Imagine a typical high-rise building in Kuala Lumpur: glass and concrete shimmering under the intense tropical sun. For decades, this solar radiation was a challenge to be mitigated. Today, it is being harnessed. Solar thermal systems, which convert sunlight into usable heat, are emerging as a viable and efficient technology to power everything from the hot water in your shower to the climate control of an entire building. For a nation blessed with abundant sunlight, unlocking this potential is key to a sustainable, energy-independent urban future.
Malaysia's solar radiation levels
Required EUI for 40-story net-zero buildings2
Mean efficiency of DLVB harvesting system
Malaysia's solar energy potential is significant, with solar radiation levels ranging from 4.21 to 5.56 kWh/m². This abundant resource presents a golden opportunity for renewable energy. However, the path to sustainability for high-rise buildings is fraught with unique challenges.
A critical scientific study highlighted a fundamental issue: the taller a building gets, the harder it becomes to achieve net-zero energy status2 .
This is because the Energy Use Intensity (EUI)—the annual energy consumption per square meter of floor space—must be extremely low to be offset by the limited roof area available for solar panels2 . For a 40-story building, the permitted EUI would need to be a stringent 17–24 kWh/m²a, a figure that is far more demanding than even the most stringent building codes and is difficult to achieve with conventional designs2 .
Furthermore, the buildings themselves alter the urban climate. The widespread use of concrete and brick in urban areas creates an Urban Heat Island (UHI) effect, where these heavy materials absorb solar radiation by day and release it slowly at night, raising ambient temperatures7 . This effect is often trapped within "urban canyons," where tall buildings prevent wind from dispersing the warm air7 . Ironically, the quest to cool these buildings using energy-intensive air conditioning further exacerbates the problem by releasing warmer air into the surroundings7 .
Despite these challenges, practical solar thermal technologies are already making a difference in Malaysia. The most established application is in solar water heating (SWH). These systems work by using a solar thermal collector to heat a fluid, which then passes into a storage system for later use in showers, kitchens, and laundries6 .
For large-scale applications like hospitals, this can lead to substantial savings. One hospital in Ipoh reported that its investment in a solar hot water system, used for laundry, kitchen, and hostel bathrooms, was successfully recouped through significant cuts in its electricity bill1 .
Beyond water heating, heat pumps are gaining traction for their efficiency in heating swimming pools and spas. As one engineering consultant noted, "Heat pumps use very little electrical energy to heat up the pool and spa water, some models can even convert the electrical energy to heat energy with the ratio of 1 to 6"1 .
While solar panels for electricity (photovoltaics) get most of the attention, a cutting-edge experiment in Malaysia is exploring a different angle: harvesting the immense thermal energy that builds up on building roofs.
Researchers at the Tun Hussein Onn University of Malaysia designed a novel experiment to capture the waste heat absorbed by roofs—a major contributor to building heat gain in the tropics.
The voltage from a TEG is not only low (often below 2 volts) but also "bipolar," meaning its polarity can flip unpredictably depending on which side of the module is hotter—a common occurrence with fluctuating sunlight.
The team developed a Dual-Level Voltage Bipolar (DLVB) harvesting system. This sophisticated circuit was designed to handle the unpredictable polarity and boost the low voltage to a usable level efficiently.
The circuit was first tested in the lab at constant and varying time intervals. Subsequently, a field test was conducted to evaluate its performance in a real-world environment, measuring input and output power to calculate efficiency.
The experiment was a resounding success. The DLVB harvesting circuit proved capable of boosting TEG input voltages as low as 0.6 and 1.6 volts to a stable, usable level. Most impressively, the circuit maintained a mean efficiency of 91.92% during tests, with field efficiency ranging between 89.62% and 92.98%. The output power, once a negligible trickle, was boosted to a range of 1.45 to 66.1 milliwatts per module. This demonstrated that with the right technology, the scorching heat on a building's roof can be reliably converted into a small but useful power source for sensors or other low-energy devices.
| Tool/Component | Function in Research & Development |
|---|---|
| Thermoelectric Generator (TEG) | The core device that converts a temperature difference into electrical voltage. |
| Solar Thermal Collector | A panel that absorbs sunlight to heat a fluid (water or antifreeze). |
| Heat Pump | A device that moves heat from one location to another using very little electrical energy. |
| Double Pass Solar Air Thermal Collector | A system that increases efficiency by passing air twice over a heated surface for enhanced heat transfer5 . |
| Maximum Power Point Tracking (MPPT) | A smart electronic algorithm that ensures the energy harvesting system extracts the maximum possible power from the TEG or solar panel at any given moment. |
| DC-DC Boost Converter | An electronic circuit that increases the low voltage from a TEG to a higher, more usable voltage level. |
The future of solar thermal in high-rises lies in integration. Scientists in China are developing a colorless window coating made from cholesteric liquid crystals (CLCs) that can redirect ambient light to solar cells at the edges of the glass without distorting the view4 . It is estimated that a standard window fitted with this technology could multiply the solar energy gathered by 50 times4 .
Such Building Integrated Photovoltaics (BIPV), where the solar technology is part of the building material itself, is an emerging trend that could turn a building's entire facade into a power generator8 .
Continuous research is also vital. Institutions like the Solar Energy Research Institute (SERI) in Malaysia are actively working on improving solar thermal technology, focusing on PV cooling systems, advanced collectors, and solar cooling5 . This ongoing innovation is essential for driving efficiency and lowering costs.
The journey to power Malaysia's high-rise buildings with solar thermal energy is well underway. From the established success of solar water heaters in hospitals to the promising frontier of heat-scavenging roof tiles and power-generating windows, the technology is evolving rapidly. While high-rises present a unique set of challenges, they also offer vast surfaces to capture the sun's generous energy. By embracing integrated design and supporting continuous research, Malaysia can transform its urban skylines into models of sustainability, where the sun's heat not only powers our lives but also cools our cities.