Communities in PRCR
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- Colecciones de la Albizu University
- Colecciones digitales de Atenas College
- Colecciones de los Centros Sor Isolina Ferré
- Materiales utilizados para la certificación.
Recent Submissions
Retrofit Heat-Recovery Ventilation for an Office Building with Exhaust Heat Recovery
(Polytechnic University of Puerto Rico, 2026) Colón Espinosa, Luis J.; Cruzado Vélez, Héctor J.
This study evaluated a retrofit heat recovery ventilation (HRV) system for a 70,000 ft², seven-story office building to reduce ventilation-related heating energy, improve indoor air quality (IAQ), and integrate with existing HVAC controls while minimizing disruption. A compact plate-type HRV with CO₂-based demand controls was selected. Phased installation and commissioning included test and balance procedures, control interlocks with the rooftop unit, and staff training. Twelve-month monitoring with 15-minute logging of energy and IAQ metrics showed a mean sensible heat-exchanger effectiveness of 72%, an 18% annual reduction in ventilation-related space-heating energy, and a reduction in occupied-hour CO₂ peak concentrations from values exceeding 1,200 ppm to sustained levels below 950 ppm. Integrated controls prevented overventilation and maintained occupant comfort. The estimated simple payback period ranged from 5 to 7 years. The retrofit demonstrated that a compact, well-commissioned HRV with demand control delivered measurable energy, IAQ, and operational benefits for midrise office buildings. Key Terms: Demand controlled ventilation (CO2 based), Retrofit commissioning, Sensible heat exchanger effectiveness, Ventilation related energy savings.
Coordination of Multiple Engineering Teams at Substation Sites for Deadline Compliance
(Polytechnic University of Puerto Rico, 2026) Sanabria Santiago, Luis R.; Cruzado Vélez, Héctor J.
Electrical substations are critical components of power systems, yet construction projects frequently experience delays caused by design changes, procurement issues, coordination problems, material delivery delays, and conflicts between construction activities. This study evaluated a structured scheduling framework developed to improve coordination and reduce project delays in electrical substation construction. The framework was implemented through a pilot project and included logic ties, resource allocation, contingency buffers, digital scheduling tools, daily check-ins, assigned team leads, phased access protocols, weekly progress reviews, standardized procedures, training, and automated reporting mechanisms. Project performance was assessed by comparing documented issues before and during implementation. Results showed that total documented issues decreased from 13 before the pilot to 3 during implementation, representing a 77% overall reduction. Design coordination, deadlines and construction dates, and material ordering each achieved a 100% reduction in documented issues. Construction-related issues decreased by 75%, while meeting-related issues decreased by 50%. These findings demonstrate measurable improvements in coordination, communication, procurement alignment, and construction activity management.
Optimization of the Production Process of Transfer Switch in a Manufacturing Environment
(2026) Marte Sostre, Manuel; Cruzado Vélez, Héctor J.
This project aimed to optimize the manufacturing process of ATS-100A automatic transfer switches in a manufacturing environment. Production was limited to 11 units per week on average due to inefficiencies, bottlenecks, and non-value-added activities. When the project began, in the first five weeks 55 units were produced compared to 120 planned units, evidenced by a difference of 65 units. The DMAIC methodology was applied to analyze the process, including time studies at workstations and the use of tools such as the Pareto chart to identify root causes. In the improvement phase, actions such as the establishment of standards, unification of production plans, and definition of minimums and maximums in inventories were implemented. These improvements aimed to reduce cycle times and increase the manufacturing production output and capacity to 24 units per week.
Process and Design Control Improvements to Prevent Tray Seal Defects in Medical Device Packaging
(Polytechnic University of Puerto Rico, 2026) Fiallo Marquina, María Patricia; Cruzado Vélez, Héctor J.
Tray seal variability in sterile medical device packaging can affect package consistency and reduce the effectiveness of inspection controls. This project evaluated abnormal seal width and Tyvek marking observed in thermoformed trays at a medical device manufacturing facility. A DMAIC-based approach was used, including record review, process mapping, dimensional assessment, and cause-and-effect analysis. The investigation identified three main contributors: supplier-generated flange variation during tray trimming, equipment setup associated with abnormal Tyvek marks, and unclear inspection criteria for seal width and mark interpretation. Supplier investigation found flange widths as low as 0.25 in., below the minimum acceptable width of 0.28 in. Corrective actions included revision of design and inspection requirements, supplier die-cutting improvements, and implementation of a Go/No-Go inspection. These actions strengthen packaging controls and support reliability.