Integrating FPGAs with a general purpose computer remains difficult, but recent efforts have resulted in open frameworks that offer a software API and hardware interface to allow easier integration. However, such systems only support static FPGA designs. With the addition of partial reconfiguration (PR) support, such frameworks can enable more effective use of FPGAs. Now, designers can incorporate hardware accelerators within their software applications, and these can be loaded dynamically as required. We present a PR-enabled FPGA platform that allows user modules to be loaded onto the FPGA, inputs to be applied, results obtained, and functions to be swapped at runtime. The interface and PR management logic are part of the static region, while multiple accelerators can be loaded using high level functions provided by the API. Reconfiguration and data transfer are both managed over the PCIe interface from the host PC, with communication throughput of more than 1.5 GB/s (75% of peak PCIe bandwidth) and reconfiguration of a large accelerator in 20 ms.