Vi H. Rapp, PhD

In collaboration with a team from Boston Children’s Hospital, we advancing an infant warmer design that can be used globally in resource-limited locations to prevent neonatal hypothermia. A first iteration of the infant warmer has been field tested with success in Rwanda. Based on user feedback, we are further improving the design for mass manufacturing, while ensuing it can be reused up to 100 times, remains non-electric and easy to clean, and can be produced at low cost.

This project aims to develop a novel and cost effective process for creating advanced thermoelectric (TE) materials constructed from Si Nanowires (Si-nw) arrays, and to demonstrate, with a prototype device, its performance and ability to scale to mass-production for heat-to-electricity conversion. Implementing Si-nw will create a cost effective waste heat recovery system capable of achieving a heat-to-electricity conversion efficiency of at least 10% (~2.5 times more than market TE).

For this project, we developed a stove that reduced harmful emissions by at least 90% per meal. Knowledge gained during design, development, and testing was transferred to the cookstoves research community, by means of publications, conferences, and in-person training. This research also supported development and publication of ISO ISO 19867-1.

Building from the California Energy Commission funded project developing a residential cooktop burner (see below), we have partnered with industry to evaluate the performance of the burner in a commercial appliance. If successful, this burner will be integrated into a their new line of technology.

For the ARPA-E GENSETS program, we developed a robust, scalable, and fuel flexible burner and heat exchanger system for state-of-the-art Stirling engine power generation systems. For the combustor, we adapted the low-swirl burner technology for use with a Stirling engine heater head. This engine heater head will provide ultra-low emissions while improving heat transfer efficiency to the working fluid of the engine.

This project developed an efficient, cost-effective, ultra-low emissions natural gas on-demand (tankless) water heater for commercial and residential buildings. The new design integrates the low swirl burner (LSB), developed at Berkeley Lab, which circumvents complicated burner staging practices and offers high-performance (30:1 turndown) with ultra low emissions.

This project adapted the Lawrence Berkeley National Laboratory (LBNL) Ring-Stabilizer Burner combustion technology for residential and commercial natural gas fired cooking appliances (such as ovens, ranges, and cooktops). This natural draft combustion technology reduces NOx emissions significantly below current SCAQMD emissions standards without post combustion treatment.

This project investigated the effects of varying natural gas blends and associated Wobbe number (a measure of the energy delivery rate for appliances that use orifice- or pressure-based fuel metering) on pollutant emissions from residential water heaters. The most prominent finding was an increase in NOX emissions with increasing Wobbe number. The largest percentage increases occurred for the ultra low-NOX water heaters.

This project investigated the effectiveness of test methods used to assess the potential for depressurization-induced backdrafting and spillage. The success of this research led to invited presentations, interviews, and changes in policy and testing standards for combustion safety testing.