Timber V4ult – Energy Systems

Team member(s): Atticus Cummings, Shannon Shahan, Breno Martinelli and Shivani Edukulla
Modified by Atticus Cummings on February 10, 2025

We are developing an innovative mixed use project in the Sant Adria de Besos area of Barcelona, the project will hose a modular wood building factory with offices and two floors of residential units as well as public green space. The project represents Besos’ transition from an old industrial area into a cutting edge neighborhood at the forefront of Barcelona’s journey toward self-sufficiency.

Energy Systems Integration

We have modeled and analyzed a photovoltaic PV system to provide energy to the Timber V4ult project. A high-efficiency PV system is located on the roof and raised on a pergola system to simultaneously provide power generation and a shaded roof terrace. We also analyzed a phase change material system for its capacity to reduce the energy requirements of the HVAC system.

To understand the capacity of our design to generate its own power we calculated our energy and power requirements based on the program and size of the spaces within the project.

Energy and Power requirements

Energy Requirement: as calculated from the program

Photovoltaic System

We used the web-platform SunnyDesign to calculate and compare PV solar systems and determine the self-sufficiency and carbon sequestration of the building based on our energy requirements.

Sunny design calculations for roof PV indicating we could achieve almost 40% self-sufficiency with the rooftop PV array.

The energy balance graph shows the building’s ability to generate power, the power that will be fed into the grid due to overproduction during the day, and the electrical load of the building for each month.

Information provided by sunny design on the self consumption of the building (how much of the energy generated on site is used on site)

Results from our analysis in sunny design showing that the earnings from selling energy back to the grid, the self-sufficiency on the PV array alone, the amount saved in energy costs each month, and the carbon dioxide reductions after 20 years.

Is PV worth it?

Based on our calculations, including the solar array in our final design is an excellent investment.

PV array design

SunnyDesign allows the designer or engineer to see the layout of the PV arrays on the skin of the building in a simplified geometric form. This helped us understand the spatial requirements of the PV system and how it could integrate with the design.

Integration of the Energy Systems Into the Design: Pergola

Phase Change Materials (PCM)

Phase Change Materials function like thermal mass. By harnessing the energy of transition this biobased passive system helps stabilize the temperature in the building and reduces both HVAC energy usage and the number of times the HVAC system needs to cycle thus saving energy and carbon emissions, and extending the lifespan of the HVAC system.

Phase Change Material solutions by Phase Change Material Products Limited UK.

Space requirements: 0.5 ceiling space.

Cost: $4k to $5.5K USD per 100m2 of space.

Assuming only 50% coverage of the ceiling area with TubeICE, the design provides approximately 87 kWh (24.7 TR-h) energy storage capacity for 100 m2 (1,000 ft2) space.

Rough numbers for precedent study based on industry reports: ~ 30% reduction on HVAC Cost, ~ 3 years ROI, ~ 150,000 Euro investment, ~ 40,000 kWh load reduction (Phase Change Solutions USA).

Are PCMs worth it:

Based on our research a PCM would be a worthwhile investment.

Integration with Besos District Heating/Cooling System

We will connect with the Sant Adrià de Besòs district heating and cooling system to fulfill the remaining needs of our building.

Floor -1 design showing integration of technical spaces that will be required for the electrical and HVAC systems

Comparison of PV and PCM systems

We conducted a financial and carbon analysis of both the PV and PCM systems to determine the financial and environmental value of implementation in our building.

PV System Payback Period

Investment Cost: 266,220.00 EUR
Total Savings after 20 years: 342,682 EUR

Total Savings a year: 342,682/20 = 17,134.10 EUR

Electricity Costs Saved after 20 years: 716,203 EUR

Electricity Costs Saved per year: 716,203/20 = 35,810.15 EUR

Payback Period Calculation:

Payback Period: Cost of Investment/(Annual Cash Flow: Total Savings + Electricity
Costs Saved per year )
Payback Period: 266,220/(17,134.10 + 35,810.15) = 5.04 years

PV Carbon reduction

1,430 t of CO2 reduction after 20 years.

PCM System Payback Period

Investment Cost: 150,000 EUR
Annual Cash Flow: Annual Energy Savings X Electricity Cost per kWh
Annual Cash Flow: (Energy Savings = 449,200kWh (Pre-installation consumption) −
408,772 (Post energy savings consumption) kWh) = 40,428 kWh x 0.2436 EUR/kWh
(Spain estimates) = 9,847.80 EUR
Payback Period Calculation: Cost of Investment/Annual Cash Flow
Payback Period: 150,000 EUR/9847.80 EUR = 15.23 years

PCM system carbon reductions

543.75 t of carbon reduction after 20 years.

Conclusion

Both rooftop PV and PCM systems provide significant potential for cost savings and carbon dioxide reduction. We would recommend using both systems in our building.

If, for budget reasons, only one system were to be chosen it should be the PV system because it pays for 3X itself faster and has the potential to offset 2X more carbon emissions compared to the PCM system.

References and resources:

Sunny Design:

https://www.sunnydesignweb.com/sdweb#/Home

Besos District Heating:

https://www.construction21.org/data/exports/pdf/districlima-urban-network-of-heat-and-cold-in-barcelona-and-sant-adria-de-besos.pdf

http://aaltopro2.aalto.fi/projects/up-res/DHC%20BARCELONA_CHRISTOPH%20PETERS.pdf

Phase Change Materials:

https://www.pcmproducts.net/PCM_Products_Background.htm